From 78af2b4630ccde4b03659a259f739f83ae0de9ec Mon Sep 17 00:00:00 2001
From: rojaro <>
Date: Mon, 13 Jul 2009 14:02:17 +0000
Subject: - ActiveRecord Port from Yii ... not perfect but works ^^

---
 .gitattributes                                     |   30 +
 .../DEPRECATED_COMPATIBILITY_REASONS_ONLY          |    3 +
 .../Relations/TActiveRecordRelationContext.php     |  230 +++
 framework/Db/ActiveRecord/TActiveFinder.php        | 1279 ++++++++++++++
 framework/Db/ActiveRecord/TActiveRecord.php        | 1843 ++++++++++++++++++++
 .../Db/ActiveRecord/TActiveRecordBehavior.php      |   94 +
 .../Db/ActiveRecord/TActiveRecordCriteria.php      |  254 +++
 framework/Db/Schema/TDbColumnSchema.php            |  145 ++
 framework/Db/Schema/TDbCommandBuilder.php          |  656 +++++++
 framework/Db/Schema/TDbCriteria.php                |  166 ++
 framework/Db/Schema/TDbExpression.php              |   49 +
 framework/Db/Schema/TDbSchema.php                  |  193 ++
 framework/Db/Schema/TDbTableSchema.php             |   76 +
 framework/Db/Schema/mssql/TMssqlColumnSchema.php   |   57 +
 framework/Db/Schema/mssql/TMssqlCommandBuilder.php |  303 ++++
 framework/Db/Schema/mssql/TMssqlPdoAdapter.php     |   74 +
 framework/Db/Schema/mssql/TMssqlSchema.php         |  312 ++++
 framework/Db/Schema/mssql/TMssqlTableSchema.php    |   35 +
 framework/Db/Schema/mysql/TMysqlColumnSchema.php   |   46 +
 framework/Db/Schema/mysql/TMysqlSchema.php         |  205 +++
 framework/Db/Schema/mysql/TMysqlTableSchema.php    |   26 +
 framework/Db/Schema/oci/TOciColumnSchema.php       |   56 +
 framework/Db/Schema/oci/TOciCommandBuilder.php     |  122 ++
 framework/Db/Schema/oci/TOciSchema.php             |  278 +++
 framework/Db/Schema/oci/TOciTableSchema.php        |   28 +
 framework/Db/Schema/pgsql/TPgsqlColumnSchema.php   |   58 +
 framework/Db/Schema/pgsql/TPgsqlSchema.php         |  284 +++
 framework/Db/Schema/pgsql/TPgsqlTableSchema.php    |   27 +
 framework/Db/Schema/sqlite/TSqliteColumnSchema.php |   35 +
 .../Db/Schema/sqlite/TSqliteCommandBuilder.php     |   43 +
 framework/Db/Schema/sqlite/TSqliteSchema.php       |  134 ++
 31 files changed, 7141 insertions(+)
 create mode 100644 framework/Db/ActiveRecord/Relations/DEPRECATED_COMPATIBILITY_REASONS_ONLY
 create mode 100644 framework/Db/ActiveRecord/Relations/TActiveRecordRelationContext.php
 create mode 100644 framework/Db/ActiveRecord/TActiveFinder.php
 create mode 100644 framework/Db/ActiveRecord/TActiveRecord.php
 create mode 100644 framework/Db/ActiveRecord/TActiveRecordBehavior.php
 create mode 100644 framework/Db/ActiveRecord/TActiveRecordCriteria.php
 create mode 100755 framework/Db/Schema/TDbColumnSchema.php
 create mode 100755 framework/Db/Schema/TDbCommandBuilder.php
 create mode 100755 framework/Db/Schema/TDbCriteria.php
 create mode 100755 framework/Db/Schema/TDbExpression.php
 create mode 100755 framework/Db/Schema/TDbSchema.php
 create mode 100755 framework/Db/Schema/TDbTableSchema.php
 create mode 100755 framework/Db/Schema/mssql/TMssqlColumnSchema.php
 create mode 100755 framework/Db/Schema/mssql/TMssqlCommandBuilder.php
 create mode 100755 framework/Db/Schema/mssql/TMssqlPdoAdapter.php
 create mode 100755 framework/Db/Schema/mssql/TMssqlSchema.php
 create mode 100755 framework/Db/Schema/mssql/TMssqlTableSchema.php
 create mode 100755 framework/Db/Schema/mysql/TMysqlColumnSchema.php
 create mode 100755 framework/Db/Schema/mysql/TMysqlSchema.php
 create mode 100755 framework/Db/Schema/mysql/TMysqlTableSchema.php
 create mode 100755 framework/Db/Schema/oci/TOciColumnSchema.php
 create mode 100755 framework/Db/Schema/oci/TOciCommandBuilder.php
 create mode 100755 framework/Db/Schema/oci/TOciSchema.php
 create mode 100755 framework/Db/Schema/oci/TOciTableSchema.php
 create mode 100755 framework/Db/Schema/pgsql/TPgsqlColumnSchema.php
 create mode 100755 framework/Db/Schema/pgsql/TPgsqlSchema.php
 create mode 100755 framework/Db/Schema/pgsql/TPgsqlTableSchema.php
 create mode 100755 framework/Db/Schema/sqlite/TSqliteColumnSchema.php
 create mode 100755 framework/Db/Schema/sqlite/TSqliteCommandBuilder.php
 create mode 100755 framework/Db/Schema/sqlite/TSqliteSchema.php

diff --git a/.gitattributes b/.gitattributes
index 1ba435cd..5fdca142 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -2202,6 +2202,36 @@ framework/Data/TDbCommand.php -text
 framework/Data/TDbConnection.php -text
 framework/Data/TDbDataReader.php -text
 framework/Data/TDbTransaction.php -text
+framework/Db/ActiveRecord/Relations/DEPRECATED_COMPATIBILITY_REASONS_ONLY -text
+framework/Db/ActiveRecord/Relations/TActiveRecordRelationContext.php -text
+framework/Db/ActiveRecord/TActiveFinder.php -text
+framework/Db/ActiveRecord/TActiveRecord.php -text
+framework/Db/ActiveRecord/TActiveRecordBehavior.php -text
+framework/Db/ActiveRecord/TActiveRecordCriteria.php -text
+framework/Db/Schema/TDbColumnSchema.php -text
+framework/Db/Schema/TDbCommandBuilder.php -text
+framework/Db/Schema/TDbCriteria.php -text
+framework/Db/Schema/TDbExpression.php -text
+framework/Db/Schema/TDbSchema.php -text
+framework/Db/Schema/TDbTableSchema.php -text
+framework/Db/Schema/mssql/TMssqlColumnSchema.php -text
+framework/Db/Schema/mssql/TMssqlCommandBuilder.php -text
+framework/Db/Schema/mssql/TMssqlPdoAdapter.php -text
+framework/Db/Schema/mssql/TMssqlSchema.php -text
+framework/Db/Schema/mssql/TMssqlTableSchema.php -text
+framework/Db/Schema/mysql/TMysqlColumnSchema.php -text
+framework/Db/Schema/mysql/TMysqlSchema.php -text
+framework/Db/Schema/mysql/TMysqlTableSchema.php -text
+framework/Db/Schema/oci/TOciColumnSchema.php -text
+framework/Db/Schema/oci/TOciCommandBuilder.php -text
+framework/Db/Schema/oci/TOciSchema.php -text
+framework/Db/Schema/oci/TOciTableSchema.php -text
+framework/Db/Schema/pgsql/TPgsqlColumnSchema.php -text
+framework/Db/Schema/pgsql/TPgsqlSchema.php -text
+framework/Db/Schema/pgsql/TPgsqlTableSchema.php -text
+framework/Db/Schema/sqlite/TSqliteColumnSchema.php -text
+framework/Db/Schema/sqlite/TSqliteCommandBuilder.php -text
+framework/Db/Schema/sqlite/TSqliteSchema.php -text
 framework/Exceptions/TErrorHandler.php -text
 framework/Exceptions/TException.php -text
 framework/Exceptions/messages/messages-id.txt -text
diff --git a/framework/Db/ActiveRecord/Relations/DEPRECATED_COMPATIBILITY_REASONS_ONLY b/framework/Db/ActiveRecord/Relations/DEPRECATED_COMPATIBILITY_REASONS_ONLY
new file mode 100644
index 00000000..8c7a4073
--- /dev/null
+++ b/framework/Db/ActiveRecord/Relations/DEPRECATED_COMPATIBILITY_REASONS_ONLY
@@ -0,0 +1,3 @@
+Please note that this file is used for old Prado ActiveRecord applications which use $record->withAnotherRecord - syntax.
+
+You shouln't use that syntax anymore as it's deprecated in this portation of Yii ActiveRecords.
diff --git a/framework/Db/ActiveRecord/Relations/TActiveRecordRelationContext.php b/framework/Db/ActiveRecord/Relations/TActiveRecordRelationContext.php
new file mode 100644
index 00000000..696bb5b1
--- /dev/null
+++ b/framework/Db/ActiveRecord/Relations/TActiveRecordRelationContext.php
@@ -0,0 +1,230 @@
+<?php
+/**
+ * TActiveRecordRelationContext class.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2008 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.ActiveRecord.Relations
+ */
+
+/**
+ * TActiveRecordRelationContext holds information regarding record relationships
+ * such as record relation property name, query criteria and foreign object record
+ * class names.
+ *
+ * This class is use internally by passing a context to the TActiveRecordRelation
+ * constructor.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.ActiveRecord.Relations
+ * @since 3.1
+ */
+class TActiveRecordRelationContext
+{
+	private $_property;
+	private $_record;
+	private $_relation; //data from an entry of TActiveRecord::$RELATION
+	private $_fkeys;
+
+	public function __construct($record, $property=null, $relation=null)
+	{
+		$this->_record=$record;
+		$this->_property=$property;
+		$this->_relation=$relation;
+	}
+
+	/**
+	 * @return boolean true if the relation is defined in TActiveRecord::$RELATIONS
+	 * @since 3.1.2
+	 */
+	public function hasRecordRelation()
+	{
+		return $this->_relation!==null;
+	}
+
+	public function getPropertyValue()
+	{
+		$obj = $this->getSourceRecord();
+		return $obj->getColumnValue($this->getProperty());
+	}
+
+	/**
+	 * @return string name of the record property that the relationship results will be assigned to.
+	 */
+	public function getProperty()
+	{
+		return $this->_property;
+	}
+
+	/**
+	 * @return TActiveRecord the active record instance that queried for its related records.
+	 */
+	public function getSourceRecord()
+	{
+		return $this->_record;
+	}
+
+	/**
+	 * @return array foreign key of this relations, the keys is dependent on the
+	 * relationship type.
+	 * @since 3.1.2
+	 */
+	public function getRelationForeignKeys()
+	{
+		if($this->_fkeys===null)
+			$this->_fkeys=$this->getRelationHandler()->getRelationForeignKeys();
+		return $this->_fkeys;
+	}
+
+	/**
+	 * @return string HAS_MANY, HAS_ONE, or BELONGS_TO
+	 */
+	public function getRelationType()
+	{
+		return $this->_relation[0];
+	}
+
+	/**
+	 * @return string foreign record class name.
+	 */
+	public function getForeignRecordClass()
+	{
+		return $this->_relation[1];
+	}
+
+	/**
+	 * @return string foreign key field names, comma delimited.
+	 * @since 3.1.2
+	 */
+	public function getFkField()
+	{
+		return $this->_relation[2];
+	}
+
+	/**
+	 * @return string the query condition for the relation as specified in RELATIONS
+	 * @since 3.1.2
+	 */
+	public function getCondition()
+	{
+		return isset($this->_relation[3])?$this->_relation[3]:null;
+	}
+
+	/**
+	 * @return array the query parameters for the relation as specified in RELATIONS
+	 * @since 3.1.2
+	 */
+	public function getParameters()
+	{
+		return isset($this->_relation[4])?$this->_relation[4]:array();
+	}
+
+	/**
+	 * @return boolean true if the 3rd element of an TActiveRecord::$RELATION entry is set.
+	 * @since 3.1.2
+	 */
+	public function hasFkField()
+	{
+		$notManyToMany = $this->getRelationType() !== TActiveRecord::MANY_TO_MANY;
+		return $notManyToMany && isset($this->_relation[2]) && !empty($this->_relation[2]);
+	}
+
+	/**
+	 * @return string the M-N relationship association table name.
+	 */
+	public function getAssociationTable()
+	{
+		return $this->_relation[2];
+	}
+
+	/**
+	 * @return boolean true if the relationship is HAS_MANY and requires an association table.
+	 */
+	public function hasAssociationTable()
+	{
+		$isManyToMany = $this->getRelationType() === TActiveRecord::MANY_TO_MANY;
+		return $isManyToMany && isset($this->_relation[2]) && !empty($this->_relation[2]);
+	}
+
+	/**
+	 * @return TActiveRecord corresponding relationship foreign object finder instance.
+	 */
+	public function getForeignRecordFinder()
+	{
+		return TActiveRecord::finder($this->getForeignRecordClass());
+	}
+
+	/**
+	 * Creates and return the TActiveRecordRelation handler for specific relationships.
+	 * An instance of TActiveRecordHasOne, TActiveRecordBelongsTo, TActiveRecordHasMany,
+	 * or TActiveRecordHasManyAssocation will be returned.
+	 * @param TActiveRecordCriteria search criteria
+	 * @return TActiveRecordRelation record relationship handler instnace.
+	 * @throws TActiveRecordException if property is not defined or missing.
+	 */
+	public function getRelationHandler($criteria=null)
+	{
+		if(!$this->hasRecordRelation())
+		{
+			throw new TActiveRecordException('ar_undefined_relation_prop',
+				$this->_property, get_class($this->_record), 'RELATIONS');
+		}
+		if($criteria===null)
+			$criteria = new TActiveRecordCriteria($this->getCondition(), $this->getParameters());
+		switch($this->getRelationType())
+		{
+			case TActiveRecord::HAS_MANY:
+				Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordHasMany');
+				return new TActiveRecordHasMany($this, $criteria);
+			case TActiveRecord::MANY_TO_MANY:
+				Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordHasManyAssociation');
+				return new TActiveRecordHasManyAssociation($this, $criteria);
+			case TActiveRecord::HAS_ONE:
+				Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordHasOne');
+				return new TActiveRecordHasOne($this, $criteria);
+			case TActiveRecord::BELONGS_TO:
+				Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordBelongsTo');
+				return new TActiveRecordBelongsTo($this, $criteria);
+			default:
+				throw new TActiveRecordException('ar_invalid_relationship');
+		}
+	}
+
+	/**
+	 * @return TActiveRecordRelationCommand
+	 */
+	public function updateAssociatedRecords($updateBelongsTo=false)
+	{
+		$success=true;
+		foreach($this->_record->getRecordRelations() as $data)
+		{
+			list($property, $relation) = $data;
+			$belongsTo = $relation[0]==TActiveRecord::BELONGS_TO;
+			if(($updateBelongsTo && $belongsTo) || (!$updateBelongsTo && !$belongsTo))
+			{
+				$obj = $this->getSourceRecord();
+				if(!$this->isEmptyFkObject($obj->getColumnValue($property)))
+				{
+					$context = new TActiveRecordRelationContext($this->getSourceRecord(),$property,$relation);
+					$success = $context->getRelationHandler()->updateAssociatedRecords() && $success;
+				}
+			}
+		}
+		return $success;
+	}
+
+	protected function isEmptyFkObject($obj)
+	{
+		if(is_object($obj))
+			return $obj instanceof TList ? $obj->count() === 0 : false;
+		else if(is_array($obj))
+			return count($obj)===0;
+		else
+			return empty($obj);
+	}
+}
+
diff --git a/framework/Db/ActiveRecord/TActiveFinder.php b/framework/Db/ActiveRecord/TActiveFinder.php
new file mode 100644
index 00000000..d55074c0
--- /dev/null
+++ b/framework/Db/ActiveRecord/TActiveFinder.php
@@ -0,0 +1,1279 @@
+<?php
+/**
+ * CActiveRecord class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/CBaseActiveRelation*/
+
+/**
+ * CActiveFinder implements eager loading and lazy loading of related active records.
+ *
+ * When used in eager loading, this class provides the same set of find methods as
+ * {@link CActiveRecord}.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveFinder.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class TActiveFinder extends TComponent
+{
+	/**
+	 * @var boolean join all tables all at once. Defaults to false.
+	 * This property is internally used.
+	 * @since 1.0.2
+	 */
+	public $joinAll=false;
+	/**
+	 * @var boolean whether the base model has limit or offset.
+	 * This property is internally used.
+	 * @since 1.0.2
+	 */
+	public $baseLimited=false;
+
+	private $_joinCount=0;
+	private $_joinTree;
+	private $_builder;
+	private $_criteria;  // the criteria generated via named scope
+
+	/**
+	 * Constructor.
+	 * A join tree is built up based on the declared relationships between active record classes.
+	 * @param CActiveRecord the model that initiates the active finding process
+	 * @param mixed the relation names to be actively looked for
+	 * @param CDbCriteria the criteria associated with the named scopes (since version 1.0.5)
+	 */
+	public function __construct($model,$with,$criteria=null)
+	{
+		$this->_criteria=$criteria;
+		$this->_builder=$model->getCommandBuilder();
+		$this->_joinTree=new TJoinElement($this,$model);
+		$this->buildJoinTree($this->_joinTree,$with);
+	}
+
+	/**
+	 * Uses the most aggressive join approach.
+	 * By calling this method, even if there is LIMIT/OFFSET option set for
+	 * the primary table query, we will still use a single SQL statement.
+	 * By default (without calling this method), the primary table will be queried
+	 * by itself so that LIMIT/OFFSET can be correctly applied.
+	 * @return CActiveFinder the finder object
+	 * @since 1.0.2
+	 */
+	public function together()
+	{
+		$this->joinAll=true;
+		return $this;
+	}
+
+	private function query($criteria,$all=false)
+	{
+		if($this->_criteria!==null)
+		{
+			$this->_criteria->mergeWith($criteria);
+			$criteria=$this->_criteria;
+		}
+
+		$this->_joinTree->find($criteria);
+		$this->_joinTree->afterFind();
+
+		if($all)
+			return array_values($this->_joinTree->records);
+		else if(count($this->_joinTree->records))
+			return reset($this->_joinTree->records);
+		else
+			return null;
+	}
+
+	/**
+	 * This is the relational version of {@link CActiveRecord::find()}.
+	 */
+	public function find($condition='',$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.find() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->_builder->createCriteria($condition,$params);
+		return $this->query($criteria);
+	}
+
+	/**
+	 * This is the relational version of {@link CActiveRecord::findAll()}.
+	 */
+	public function findAll($condition='',$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.findAll() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->_builder->createCriteria($condition,$params);
+		return $this->query($criteria,true);
+	}
+
+	/**
+	 * This is the relational version of {@link CActiveRecord::findByPk()}.
+	 */
+	public function findByPk($pk,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.findByPk() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->_builder->createPkCriteria($this->_joinTree->model->getTableSchema(),$pk,$condition,$params);
+		return $this->query($criteria);
+	}
+
+	/**
+	 * This is the relational version of {@link CActiveRecord::findAllByPk()}.
+	 */
+	public function findAllByPk($pk,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.findAllByPk() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->_builder->createPkCriteria($this->_joinTree->model->getTableSchema(),$pk,$condition,$params);
+		return $this->query($criteria,true);
+	}
+
+	/**
+	 * This is  the relational version of {@link CActiveRecord::findByAttributes()}.
+	 */
+	public function findByAttributes($attributes,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.findByAttributes() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->_builder->createColumnCriteria($this->_joinTree->model->getTableSchema(),$attributes,$condition,$params);
+		return $this->query($criteria);
+	}
+
+	/**
+	 * This is the relational version of {@link CActiveRecord::findAllByAttributes()}.
+	 */
+	public function findAllByAttributes($attributes,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.findAllByAttributes() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->_builder->createColumnCriteria($this->_joinTree->model->getTableSchema(),$attributes,$condition,$params);
+		return $this->query($criteria,true);
+	}
+
+	/**
+	 * This is the relational version of {@link CActiveRecord::findBySql()}.
+	 */
+	public function findBySql($sql,$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.findBySql() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		if(($row=$this->_builder->createSqlCommand($sql,$params)->queryRow())!==false)
+		{
+			$baseRecord=$this->_joinTree->model->populateRecord($row,false);
+			$this->_joinTree->findWithBase($baseRecord);
+			$this->_joinTree->afterFind();
+			return $baseRecord;
+		}
+	}
+
+	/**
+	 * This is the relational version of {@link CActiveRecord::findAllBySql()}.
+	 */
+	public function findAllBySql($sql,$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.findAllBySql() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		if(($rows=$this->_builder->createSqlCommand($sql,$params)->queryAll())!==array())
+		{
+			$baseRecords=$this->_joinTree->model->populateRecords($rows,false);
+			$this->_joinTree->findWithBase($baseRecords);
+			$this->_joinTree->afterFind();
+			return $baseRecords;
+		}
+		else
+			return array();
+	}
+
+	/**
+	 * This is the relational version of {@link CActiveRecord::count()}.
+	 * @since 1.0.3
+	 */
+	public function count($condition='',$params=array())
+	{
+		Prado::trace(get_class($this->_joinTree->model).'.count() eagerly','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->_builder->createCriteria($condition,$params);
+		if($this->_criteria!==null)
+		{
+			$this->_criteria->mergeWith($criteria);
+			$criteria=$this->_criteria;
+		}
+		return $this->_joinTree->count($criteria);
+	}
+
+	/**
+	 * Finds the related objects for the specified active record.
+	 * This method is internally invoked by {@link CActiveRecord} to support lazy loading.
+	 * @param CActiveRecord the base record whose related objects are to be loaded
+	 */
+	public function lazyFind($baseRecord)
+	{
+		$this->_joinTree->lazyFind($baseRecord);
+		if(!empty($this->_joinTree->children))
+		{
+			$child=reset($this->_joinTree->children);
+			$child->afterFind();
+		}
+	}
+
+	/**
+	 * Builds up the join tree representing the relationships involved in this query.
+	 * @param CJoinElement the parent tree node
+	 * @param mixed the names of the related objects relative to the parent tree node
+	 * @param array additional query options to be merged with the relation
+	 */
+	private function buildJoinTree($parent,$with,$options=null)
+	{
+		if($parent instanceof CStatElement)
+			throw new TDbException('The STAT relation "'.($parent->relation->name).'" cannot have child relations.');
+
+		if(is_string($with))
+		{
+			if(($pos=strrpos($with,'.'))!==false)
+			{
+				$parent=$this->buildJoinTree($parent,substr($with,0,$pos));
+				$with=substr($with,$pos+1);
+			}
+
+			// named scope
+			if(($pos=strpos($with,':'))!==false)
+			{
+				$scopes=explode(':',substr($with,$pos+1));
+				$with=substr($with,0,$pos);
+			}
+
+			if(isset($parent->children[$with]))
+				return $parent->children[$with];
+
+			if(($relation=$parent->model->getActiveRelation($with))===null)
+				throw new TDbException('Relation "'.$with.'" is not defined in active record class "'.get_class($parent->model).'".');
+
+			$relation=clone $relation;
+			$model=TActiveRecord::model($relation->className);
+			if(($scope=$model->defaultScope())!==array())
+				$relation->mergeWith($scope);
+			if(isset($scopes) && !empty($scopes))
+			{
+				$scs=$model->scopes();
+				foreach($scopes as $scope)
+				{
+					if(isset($scs[$scope]))
+						$relation->mergeWith($scs[$scope]);
+					else
+						throw new TDbException('Active record class "'.get_class($model).'" does not have a scope named "'.$scope.'".');
+				}
+			}
+
+			// dynamic options
+			if($options!==null)
+				$relation->mergeWith($options);
+
+			if($relation instanceof TStatRelation)
+				return new TStatElement($this,$relation,$parent);
+			else
+			{
+				$element=$parent->children[$with]=new TJoinElement($this,$relation,$parent,++$this->_joinCount);
+				if(!empty($relation->with))
+					$this->buildJoinTree($element,$relation->with);
+				return $element;
+			}
+		}
+
+		// $with is an array, keys are relation name, values are relation spec
+		foreach($with as $key=>$value)
+		{
+			if(is_string($value))  // the value is a relation name
+				$this->buildJoinTree($parent,$value);
+			else if(is_string($key) && is_array($value))
+				$element=$this->buildJoinTree($parent,$key,$value);
+		}
+	}
+}
+
+
+/**
+ * CJoinElement represents a tree node in the join tree created by {@link CActiveFinder}.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveFinder.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class TJoinElement
+{
+	/**
+	 * @var integer the unique ID of this tree node
+	 */
+	public $id;
+	/**
+	 * @var CActiveRelation the relation represented by this tree node
+	 */
+	public $relation;
+	/**
+	 * @var CActiveRecord the model associated with this tree node
+	 */
+	public $model;
+	/**
+	 * @var array list of active records found by the queries. They are indexed by primary key values.
+	 */
+	public $records=array();
+	/**
+	 * @var array list of child join elements
+	 */
+	public $children=array();
+	/**
+	 * @var array list of stat elements
+	 * @since 1.0.4
+	 */
+	public $stats=array();
+	/**
+	 * @var string table alias for this join element
+	 */
+	public $tableAlias;
+
+	private $_finder;
+	private $_builder;
+	private $_parent;
+	private $_pkAlias;  				// string or name=>alias
+	private $_columnAliases=array();	// name=>alias
+	private $_joined=false;
+	private $_table;
+	private $_related=array();			// PK, relation name, related PK => true
+
+	/**
+	 * Constructor.
+	 * @param CActiveFinder the finder
+	 * @param mixed the relation (if the third parameter is not null)
+	 * or the model (if the third parameter is null) associated with this tree node.
+	 * @param CJoinElement the parent tree node
+	 * @param integer the ID of this tree node that is unique among all the tree nodes
+	 */
+	public function __construct($finder,$relation,$parent=null,$id=0)
+	{
+		$this->_finder=$finder;
+		$this->id=$id;
+		if($parent!==null)
+		{
+			$this->relation=$relation;
+			$this->_parent=$parent;
+			$this->_builder=$parent->_builder;
+			$this->tableAlias=$relation->alias===null?$relation->name:$relation->alias;
+			$this->model=TActiveRecord::model($relation->className);
+			$this->_table=$this->model->getTableSchema();
+		}
+		else  // root element, the first parameter is the model.
+		{
+			$this->model=$relation;
+			$this->_builder=$relation->getCommandBuilder();
+			$this->_table=$relation->getTableSchema();
+		}
+
+		// set up column aliases, such as t1_c2
+		$table=$this->_table;
+		$prefix='t'.$id.'_c';
+		foreach($table->getColumnNames() as $key=>$name)
+		{
+			$alias=$prefix.$key;
+			$this->_columnAliases[$name]=$alias;
+			if($table->primaryKey===$name)
+				$this->_pkAlias=$alias;
+			else if(is_array($table->primaryKey) && in_array($name,$table->primaryKey))
+				$this->_pkAlias[$name]=$alias;
+		}
+	}
+
+	/**
+	 * Performs the recursive finding with the criteria.
+	 * @param CDbCriteria the query criteria
+	 */
+	public function find($criteria=null)
+	{
+		if($this->_parent===null) // root element
+		{
+			$query=new TJoinQuery($this,$criteria);
+			$this->_finder->baseLimited=($criteria->offset>=0 || $criteria->limit>=0);
+			$this->buildQuery($query);
+			$this->_finder->baseLimited=false;
+			$this->runQuery($query);
+		}
+		else if(!$this->_joined && !empty($this->_parent->records)) // not joined before
+		{
+			$query=new TJoinQuery($this->_parent);
+			$this->_joined=true;
+			$query->join($this);
+			$this->buildQuery($query);
+			$this->_parent->runQuery($query);
+		}
+
+		foreach($this->children as $child) // find recursively
+			$child->find();
+
+		foreach($this->stats as $stat)
+			$stat->query();
+	}
+
+	/**
+	 * Performs lazy find with the specified base record.
+	 * @param CActiveRecord the active record whose related object is to be fetched.
+	 */
+	public function lazyFind($baseRecord)
+	{
+		if(is_string($this->_table->primaryKey))
+			$this->records[$baseRecord->{$this->_table->primaryKey}]=$baseRecord;
+		else
+		{
+			$pk=array();
+			foreach($this->_table->primaryKey as $name)
+				$pk[$name]=$baseRecord->$name;
+			$this->records[serialize($pk)]=$baseRecord;
+		}
+
+		foreach($this->stats as $stat)
+			$stat->query();
+
+		if(empty($this->children))
+			return;
+
+		$child=reset($this->children);
+		$query=new TJoinQuery($this);
+		$this->_joined=true;
+		$child->_joined=true;
+		$query->join($child);
+		if($child->relation instanceof THasManyRelation)
+		{
+			$query->limit=$child->relation->limit;
+			$query->offset=$child->relation->offset;
+			$this->_finder->baseLimited=($query->offset>=0 || $query->limit>=0);
+			$query->groups[]=$child->relation->group;
+			$query->havings[]=$child->relation->having;
+		}
+		$child->buildQuery($query);
+		$this->_finder->baseLimited=false;
+		$this->runQuery($query);
+		foreach($child->children as $c)
+			$c->find();
+	}
+
+	/**
+	 * Performs the eager loading with the base records ready.
+	 * @param mixed the available base record(s).
+	 */
+	public function findWithBase($baseRecords)
+	{
+		if(!is_array($baseRecords))
+			$baseRecords=array($baseRecords);
+		if(is_string($this->_table->primaryKey))
+		{
+			foreach($baseRecords as $baseRecord)
+				$this->records[$baseRecord->{$this->_table->primaryKey}]=$baseRecord;
+		}
+		else
+		{
+			foreach($baseRecords as $baseRecord)
+			{
+				$pk=array();
+				foreach($this->_table->primaryKey as $name)
+					$pk[$name]=$baseRecord->$name;
+				$this->records[serialize($pk)]=$baseRecord;
+			}
+		}
+
+		$query=new TJoinQuery($this);
+		$this->buildQuery($query);
+		if(count($query->joins)>1)
+			$this->runQuery($query);
+		foreach($this->children as $child)
+			$child->find();
+
+		foreach($this->stats as $stat)
+			$stat->query();
+	}
+
+	/**
+	 * Count the number of primary records returned by the join statement.
+	 * @param CDbCriteria the query criteria
+	 * @return integer number of primary records.
+	 * @since 1.0.3
+	 */
+	public function count($criteria=null)
+	{
+		$query=new TJoinQuery($this,$criteria);
+		// ensure only one big join statement is used
+		$this->_finder->baseLimited=false;
+		$this->_finder->joinAll=true;
+		$this->buildQuery($query);
+
+		if(is_string($this->_table->primaryKey))
+		{
+			$prefix=$this->getColumnPrefix();
+			$schema=$this->_builder->getSchema();
+			$column=$prefix.$schema->quoteColumnName($this->_table->primaryKey);
+		}
+		else if($criteria->select!=='*')
+			$column=$criteria->select;
+		else
+			throw new TDbException('Unable to count records with composite primary keys. Please explicitly specify the SELECT option in the query criteria.');
+
+		$query->selects=array("COUNT(DISTINCT $column)");
+		$query->orders=$query->groups=$query->havings=array();
+		$command=$query->createCommand($this->_builder);
+		return $command->queryScalar();
+	}
+
+	/**
+	 * Calls {@link CActiveRecord::afterFind} of all the records.
+	 * @since 1.0.3
+	 */
+	public function afterFind()
+	{
+		foreach($this->records as $record)
+			$record->afterFindInternal();
+		foreach($this->children as $child)
+			$child->afterFind();
+	}
+
+	/**
+	 * Builds the join query with all descendant HAS_ONE and BELONGS_TO nodes.
+	 * @param CJoinQuery the query being built up
+	 */
+	public function buildQuery($query)
+	{
+		foreach($this->children as $child)
+		{
+			if($child->relation instanceof THasOneRelation || $child->relation instanceof TBelongsToRelation
+				|| $this->_finder->joinAll || !$this->_finder->baseLimited && $child->relation->together)
+			{
+				$child->_joined=true;
+				$query->join($child);
+				$child->buildQuery($query);
+			}
+		}
+	}
+
+	/**
+	 * Executes the join query and populates the query results.
+	 * @param CJoinQuery the query to be executed.
+	 */
+	public function runQuery($query)
+	{
+		$command=$query->createCommand($this->_builder);
+		foreach($command->queryAll() as $row)
+			$this->populateRecord($query,$row);
+	}
+
+	/**
+	 * Populates the active records with the query data.
+	 * @param CJoinQuery the query executed
+	 * @param array a row of data
+	 * @return CActiveRecord the populated record
+	 */
+	private function populateRecord($query,$row)
+	{
+		// determine the primary key value
+		if(is_string($this->_pkAlias))  // single key
+		{
+			if(isset($row[$this->_pkAlias]))
+				$pk=$row[$this->_pkAlias];
+			else	// no matching related objects
+				return null;
+		}
+		else // is_array, composite key
+		{
+			$pk=array();
+			foreach($this->_pkAlias as $name=>$alias)
+			{
+				if(isset($row[$alias]))
+					$pk[$name]=$row[$alias];
+				else	// no matching related objects
+					return null;
+			}
+			$pk=serialize($pk);
+		}
+
+		// retrieve or populate the record according to the primary key value
+		if(isset($this->records[$pk]))
+			$record=$this->records[$pk];
+		else
+		{
+			$attributes=array();
+			$aliases=array_flip($this->_columnAliases);
+			foreach($row as $alias=>$value)
+			{
+				if(isset($aliases[$alias]))
+					$attributes[$aliases[$alias]]=$value;
+			}
+			$record=$this->model->populateRecord($attributes,false);
+			foreach($this->children as $child)
+				$record->addRelatedRecord($child->relation->name,null,$child->relation instanceof THasManyRelation);
+			$this->records[$pk]=$record;
+		}
+
+		// populate child records recursively
+		foreach($this->children as $child)
+		{
+			if(!isset($query->elements[$child->id]))
+				continue;
+			$childRecord=$child->populateRecord($query,$row);
+			if($child->relation instanceof THasOneRelation || $child->relation instanceof TBelongsToRelation)
+				$record->addRelatedRecord($child->relation->name,$childRecord,false);
+			else // has_many and many_many
+			{
+				// need to double check to avoid adding duplicated related objects
+				if($childRecord instanceof TActiveRecord)
+					$fpk=serialize($childRecord->getPrimaryKey());
+				else
+					$fpk=0;
+				if(!isset($this->_related[$pk][$child->relation->name][$fpk]))
+				{
+					$record->addRelatedRecord($child->relation->name,$childRecord,true);
+					$this->_related[$pk][$child->relation->name][$fpk]=true;
+				}
+			}
+		}
+
+		return $record;
+	}
+
+	/**
+	 * @return string the table name and the table alias (if any). This can be used directly in SQL query without escaping.
+	 */
+	public function getTableNameWithAlias()
+	{
+		if($this->tableAlias!==null)
+			return $this->_table->rawName . ' ' . $this->tableAlias;
+		else
+			return $this->_table->rawName;
+	}
+
+	/**
+	 * Generates the list of columns to be selected.
+	 * Columns will be properly aliased and primary keys will be added to selection if they are not specified.
+	 * @param mixed columns to be selected. Defaults to '*', indicating all columns.
+	 * @return string the column selection
+	 */
+	public function getColumnSelect($select='*')
+	{
+		$schema=$this->_builder->getSchema();
+		$prefix=$this->getColumnPrefix();
+		$columns=array();
+		if($select==='*')
+		{
+			foreach($this->_table->getColumnNames() as $name)
+				$columns[]=$prefix.$schema->quoteColumnName($name).' AS '.$schema->quoteColumnName($this->_columnAliases[$name]);
+		}
+		else
+		{
+			if(is_string($select))
+				$select=explode(',',$select);
+			$selected=array();
+			foreach($select as $name)
+			{
+				$name=trim($name);
+				$matches=array();
+				if(($pos=strrpos($name,'.'))!==false)
+					$key=substr($name,$pos+1);
+				else
+					$key=$name;
+				if(isset($this->_columnAliases[$key]))  // simple column names
+				{
+					$columns[]=$prefix.$schema->quoteColumnName($key).' AS '.$schema->quoteColumnName($this->_columnAliases[$key]);
+					$selected[$this->_columnAliases[$key]]=1;
+				}
+				else if(preg_match('/^(.*?)\s+AS\s+(\w+)$/i',$name,$matches)) // if the column is already aliased
+				{
+					$alias=$matches[2];
+					if(!isset($this->_columnAliases[$alias]) || $this->_columnAliases[$alias]!==$alias)
+					{
+						$this->_columnAliases[$alias]=$alias;
+						$columns[]=$name;
+						$selected[$alias]=1;
+					}
+				}
+				else
+					throw new TDbException('Active record "'.get_class($this->model).'" is trying to select an invalid column "'.$name.'". Note, the column must exist in the table or be an expression with alias.');
+			}
+			// add primary key selection if they are not selected
+			if(is_string($this->_pkAlias) && !isset($selected[$this->_pkAlias]))
+				$columns[]=$prefix.$schema->quoteColumnName($this->_table->primaryKey).' AS '.$schema->quoteColumnName($this->_pkAlias);
+			else if(is_array($this->_pkAlias))
+			{
+				foreach($this->_table->primaryKey as $name)
+					if(!isset($selected[$name]))
+						$columns[]=$prefix.$schema->quoteColumnName($name).' AS '.$schema->quoteColumnName($this->_pkAlias[$name]);
+			}
+		}
+
+		return implode(', ',$columns);
+	}
+
+	/**
+	 * @return string the primary key selection
+	 */
+	public function getPrimaryKeySelect()
+	{
+		$schema=$this->_builder->getSchema();
+		$prefix=$this->getColumnPrefix();
+		$columns=array();
+		if(is_string($this->_pkAlias))
+			$columns[]=$prefix.$schema->quoteColumnName($this->_table->primaryKey).' AS '.$schema->quoteColumnName($this->_pkAlias);
+		else if(is_array($this->_pkAlias))
+		{
+			foreach($this->_pkAlias as $name=>$alias)
+				$columns[]=$prefix.$schema->quoteColumnName($name).' AS '.$schema->quoteColumnName($alias);
+		}
+		return implode(', ',$columns);
+	}
+
+	/**
+	 * @return string the condition that specifies only the rows with the selected primary key values.
+	 */
+	public function getPrimaryKeyRange()
+	{
+		if(empty($this->records))
+			return '';
+		$values=array_keys($this->records);
+		if(is_array($this->_table->primaryKey))
+		{
+			foreach($values as &$value)
+				$value=unserialize($value);
+		}
+		return $this->_builder->createInCondition($this->_table,$this->_table->primaryKey,$values,$this->getColumnPrefix());
+	}
+
+	/**
+	 * @return string the column prefix for column reference disambiguation
+	 */
+	public function getColumnPrefix()
+	{
+		if($this->tableAlias!==null)
+			return $this->tableAlias.'.';
+		else
+			return $this->_table->rawName.'.';
+	}
+
+	/**
+	 * @return string the join statement (this node joins with its parent)
+	 */
+	public function getJoinCondition()
+	{
+		$parent=$this->_parent;
+		$relation=$this->relation;
+		if($this->relation instanceof TManyManyRelation)
+		{
+			if(!preg_match('/^\s*(.*?)\((.*)\)\s*$/',$this->relation->foreignKey,$matches))
+				throw new TDbException('The relation "'.($this->relation->name).'" in active record class "'.get_class($parent->model).'" is specified with an invalid foreign key. The format of the foreign key must be "joinTable(fk1,fk2,...)".');
+
+			$schema=$this->_builder->getSchema();
+			if(($joinTable=$schema->getTable($matches[1]))===null)
+				throw new TDbException('The relation "'.($this->relation->name).'" in active record class "'.get_class($parent->model).'" is not specified correctly: the join table "'.($matches[1]).'" given in the foreign key cannot be found in the database.');
+				
+			$fks=preg_split('/[\s,]+/',$matches[2],-1,PREG_SPLIT_NO_EMPTY);
+
+			return $this->joinManyMany($joinTable,$fks,$parent);
+		}
+		else
+		{
+			$fks=preg_split('/[\s,]+/',$relation->foreignKey,-1,PREG_SPLIT_NO_EMPTY);
+			if($this->relation instanceof TBelongsToRelation)
+			{
+				$pke=$this;
+				$fke=$parent;
+			}
+			else
+			{
+				$pke=$parent;
+				$fke=$this;
+			}
+			return $this->joinOneMany($fke,$fks,$pke,$parent);
+		}
+	}
+
+	/**
+	 * Generates the join statement for one-many relationship.
+	 * This works for HAS_ONE, HAS_MANY and BELONGS_TO.
+	 * @param CJoinElement the join element containing foreign keys
+	 * @param array the foreign keys
+	 * @param CJoinElement the join element containg primary keys
+	 * @param CJoinElement the parent join element
+	 * @return string the join statement
+	 * @throws CDbException if a foreign key is invalid
+	 */
+	private function joinOneMany($fke,$fks,$pke,$parent)
+	{
+		$schema=$this->_builder->getSchema();
+		$joins=array();
+		foreach($fks as $i=>$fk)
+		{
+			if(!isset($fke->_table->columns[$fk]))
+				throw new TDbException('The relation "'.($this->relation->name).'" in active record class "'.get_class($parent->model).'" is specified with an invalid foreign key "'.$fk.'". There is no such column in the table "'.($fke->_table->name).'".');
+
+			if(isset($fke->_table->foreignKeys[$fk]))
+				$pk=$fke->_table->foreignKeys[$fk][1];
+			else  // FK constraints undefined
+			{
+				if(is_array($pke->_table->primaryKey)) // composite PK
+					$pk=$pke->_table->primaryKey[$i];
+				else
+					$pk=$pke->_table->primaryKey;
+			}
+			$joins[]=$fke->getColumnPrefix().$schema->quoteColumnName($fk) . '=' . $pke->getColumnPrefix().$schema->quoteColumnName($pk);
+		}
+		if(!empty($this->relation->on))
+			$joins[]=$this->relation->on;
+		return $this->relation->joinType . ' ' . $this->getTableNameWithAlias() . ' ON (' . implode(') AND (',$joins).')';
+	}
+
+	/**
+	 * Generates the join statement for many-many relationship.
+	 * @param CDbTableSchema the join table
+	 * @param array the foreign keys
+	 * @param CJoinElement the parent join element
+	 * @return string the join statement
+	 * @throws CDbException if a foreign key is invalid
+	 */
+	private function joinManyMany($joinTable,$fks,$parent)
+	{
+		$schema=$this->_builder->getSchema();
+		$joinAlias=$this->relation->name.'_'.$this->tableAlias;
+		$parentCondition=array();
+		$childCondition=array();
+		foreach($fks as $i=>$fk)
+		{
+			if(!isset($joinTable->columns[$fk]))
+				throw new TDbException('The relation "'.($this->relation->name).'" in active record class "'.get_class($parent->model).'" is specified with an invalid foreign key "'.$fk.'". There is no such column in the table "'.($joinTable->name).'".');
+
+			if(isset($joinTable->foreignKeys[$fk]))
+			{
+				list($tableName,$pk)=$joinTable->foreignKeys[$fk];
+				if(!isset($parentCondition[$pk]) && $schema->compareTableNames($parent->_table->rawName,$tableName))
+					$parentCondition[$pk]=$parent->getColumnPrefix().$schema->quoteColumnName($pk).'='.$joinAlias.'.'.$schema->quoteColumnName($fk);
+				else if(!isset($childCondition[$pk]) && $schema->compareTableNames($this->_table->rawName,$tableName))
+					$childCondition[$pk]=$this->getColumnPrefix().$schema->quoteColumnName($pk).'='.$joinAlias.'.'.$schema->quoteColumnName($fk);
+				else
+					throw new TDbException('The relation "'.($this->relation->name).'" in active record class "'.get_class($parent->model).'" is specified with an invalid foreign key "'.$fk.'". The foreign key does not point to either joining table.');
+			}
+			else // FK constraints not defined
+			{
+				if($i<count($parent->_table->primaryKey))
+				{
+					$pk=is_array($parent->_table->primaryKey) ? $parent->_table->primaryKey[$i] : $parent->_table->primaryKey;
+					$parentCondition[$pk]=$parent->getColumnPrefix().$schema->quoteColumnName($pk).'='.$joinAlias.'.'.$schema->quoteColumnName($fk);
+				}
+				else
+				{
+					$j=$i-count($parent->_table->primaryKey);
+					$pk=is_array($this->_table->primaryKey) ? $this->_table->primaryKey[$j] : $this->_table->primaryKey;
+					$childCondition[$pk]=$this->getColumnPrefix().$schema->quoteColumnName($pk).'='.$joinAlias.'.'.$schema->quoteColumnName($fk);
+				}
+			}
+		}
+		if($parentCondition!==array() && $childCondition!==array())
+		{
+			$join=$this->relation->joinType.' '.$joinTable->rawName.' '.$joinAlias;
+			$join.=' ON ('.implode(') AND (',$parentCondition).')';
+			$join.=' '.$this->relation->joinType.' '.$this->getTableNameWithAlias();
+			$join.=' ON ('.implode(') AND (',$childCondition).')';
+			if(!empty($this->relation->on))
+				$join.=' AND ('.$this->relation->on.')';
+			return $join;
+		}
+		else
+			throw new TDbException('The relation "'.($this->relation->name).'" in active record class "'.get_class($parent->model).'" is specified with an incomplete foreign key. The foreign key must consist of columns referencing both joining tables.');
+	}
+}
+
+
+/**
+ * CJoinQuery represents a JOIN SQL statement.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveFinder.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class TJoinQuery
+{
+	/**
+	 * @var array list of column selections
+	 */
+	public $selects=array();
+	/**
+	 * @var array list of join statement
+	 */
+	public $joins=array();
+	/**
+	 * @var array list of WHERE clauses
+	 */
+	public $conditions=array();
+	/**
+	 * @var array list of ORDER BY clauses
+	 */
+	public $orders=array();
+	/**
+	 * @var array list of GROUP BY clauses
+	 */
+	public $groups=array();
+	/**
+	 * @var array list of HAVING clauses
+	 */
+	public $havings=array();
+	/**
+	 * @var integer row limit
+	 */
+	public $limit=-1;
+	/**
+	 * @var integer row offset
+	 */
+	public $offset=-1;
+	/**
+	 * @var array list of query parameters
+	 */
+	public $params=array();
+	/**
+	 * @var array list of join element IDs (id=>true)
+	 */
+	public $elements=array();
+
+	/**
+	 * Constructor.
+	 * @param CJoinElement The root join tree.
+	 * @param CDbCriteria the query criteria
+	 */
+	public function __construct($joinElement,$criteria=null)
+	{
+		if($criteria!==null)
+		{
+			$this->selects[]=$joinElement->getColumnSelect($criteria->select);
+			$this->joins[]=$joinElement->getTableNameWithAlias();
+			$this->joins[]=$criteria->join;
+			$this->conditions[]=$criteria->condition;
+			$this->orders[]=$criteria->order;
+			$this->groups[]=$criteria->group;
+			$this->havings[]=$criteria->having;
+			$this->limit=$criteria->limit;
+			$this->offset=$criteria->offset;
+			$this->params=$criteria->params;
+		}
+		else
+		{
+			$this->selects[]=$joinElement->getPrimaryKeySelect();
+			$this->joins[]=$joinElement->getTableNameWithAlias();
+			$this->conditions[]=$joinElement->getPrimaryKeyRange();
+		}
+		$this->elements[$joinElement->id]=true;
+	}
+
+	/**
+	 * Joins with another join element
+	 * @param CJoinElement the element to be joined
+	 */
+	public function join($element)
+	{
+		$this->selects[]=$element->getColumnSelect($element->relation->select);
+		$this->conditions[]=$element->relation->condition;
+		$this->orders[]=$element->relation->order;
+		$this->joins[]=$element->getJoinCondition();
+		$this->groups[]=$element->relation->group;
+		$this->havings[]=$element->relation->having;
+
+		if(is_array($element->relation->params))
+		{
+			if(is_array($this->params))
+				$this->params=array_merge($this->params,$element->relation->params);
+			else
+				$this->params=$element->relation->params;
+		}
+		$this->elements[$element->id]=true;
+	}
+
+	/**
+	 * Creates the SQL statement.
+	 * @param CDbCommandBuilder the command builder
+	 * @return string the SQL statement
+	 */
+	public function createCommand($builder)
+	{
+		$sql='SELECT ' . implode(', ',$this->selects);
+		$sql.=' FROM ' . implode(' ',$this->joins);
+
+		$conditions=array();
+		foreach($this->conditions as $condition)
+			if($condition!=='')
+				$conditions[]=$condition;
+		if($conditions!==array())
+			$sql.=' WHERE (' . implode(') AND (',$conditions).')';
+
+		$groups=array();
+		foreach($this->groups as $group)
+			if($group!=='')
+				$groups[]=$group;
+		if($groups!==array())
+			$sql.=' GROUP BY ' . implode(', ',$groups);
+
+		$havings=array();
+		foreach($this->havings as $having)
+			if($having!=='')
+				$havings[]=$having;
+		if($havings!==array())
+			$sql.=' HAVING (' . implode(') AND (',$havings).')';
+
+		$orders=array();
+		foreach($this->orders as $order)
+			if($order!=='')
+				$orders[]=$order;
+		if($orders!==array())
+			$sql.=' ORDER BY ' . implode(', ',$orders);
+
+		$sql=$builder->applyLimit($sql,$this->limit,$this->offset);
+		$command=$builder->getDbConnection()->createCommand($sql);
+		$builder->bindValues($command,$this->params);
+		return $command;
+	}
+}
+
+
+/**
+ * CStatElement represents STAT join element for {@link CActiveFinder}.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveFinder.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0.4
+ */
+class TStatElement
+{
+	/**
+	 * @var CActiveRelation the relation represented by this tree node
+	 */
+	public $relation;
+
+	private $_finder;
+	private $_parent;
+
+	/**
+	 * Constructor.
+	 * @param CActiveFinder the finder
+	 * @param CStatRelation the STAT relation
+	 * @param CJoinElement the join element owning this STAT element
+	 */
+	public function __construct($finder,$relation,$parent)
+	{
+		$this->_finder=$finder;
+		$this->_parent=$parent;
+		$this->relation=$relation;
+		$parent->stats[]=$this;
+	}
+
+	/**
+	 * Performs the STAT query.
+	 */
+	public function query()
+	{
+		if(preg_match('/^\s*(.*?)\((.*)\)\s*$/',$this->relation->foreignKey,$matches))
+			$this->queryManyMany($matches[1],$matches[2]);
+		else
+			$this->queryOneMany();
+	}
+
+	private function queryOneMany()
+	{
+		$relation=$this->relation;
+		$model=TActiveRecord::model($relation->className);
+		$builder=$model->getCommandBuilder();
+		$schema=$builder->getSchema();
+		$table=$model->getTableSchema();
+		$pkTable=$this->_parent->model->getTableSchema();
+
+		$fks=preg_split('/[\s,]+/',$relation->foreignKey,-1,PREG_SPLIT_NO_EMPTY);
+		if(count($fks)!==count($pkTable->primaryKey))
+			throw new TDbException('The relation "'.($relation->name).'" in active record class "'.get_class($parent->model).'" is specified with an invalid foreign key. The columns in the key must match the primary keys of the table "'.($pkTable->name).'".');
+
+		// set up mapping between fk and pk columns
+		$map=array();  // pk=>fk
+		foreach($fks as $i=>$fk)
+		{
+			if(!isset($table->columns[$fk]))
+				throw new TDbException('The relation "'.($relation->name).'" in active record class "'.get_class($parent->model).'" is specified with an invalid foreign key "'.$fk.'". There is no such column in the table "'.($table->name).'".');
+
+			if(isset($table->foreignKeys[$fk]))
+			{
+				list($tableName,$pk)=$table->foreignKeys[$fk];
+				if($schema->compareTableNames($pkTable->rawName,$tableName))
+					$map[$pk]=$fk;
+				else
+					throw new TDbException('The relation "'.($relation->name).'" in active record class "'.get_class($parent->model).'" is specified with a foreign key "'.$fk.'" that does not point to the parent table "'.($pkTable->name).'".');
+			}
+			else  // FK constraints undefined
+			{
+				if(is_array($table->primaryKey)) // composite PK
+					$map[$table->primaryKey[$i]]=$fk;
+			}
+		}
+
+		$records=$this->_parent->records;
+
+		$where=empty($relation->condition)?'' : ' WHERE ('.$relation->condition.')';
+		$group=empty($relation->group)?'' : ', '.$relation->group;
+		$having=empty($relation->having)?'' : ' AND ('.$relation->having.')';
+		$order=empty($relation->order)?'' : ' ORDER BY '.$relation->order;
+
+		$c=$schema->quoteColumnName('c');
+		$s=$schema->quoteColumnName('s');
+
+		// generate and perform query
+		if(count($fks)===1)  // single column FK
+		{
+			$col=$table->columns[$fks[0]]->rawName;
+			$sql="SELECT $col AS $c, {$relation->select} AS $s FROM {$table->rawName}"
+				.$where
+				." GROUP BY $col".$group
+				." HAVING ".$builder->createInCondition($table,$fks[0],array_keys($records))
+				.$having.$order;
+			$command=$builder->getDbConnection()->createCommand($sql);
+			if(is_array($relation->params))
+				$builder->bindValues($command,$relation->params);
+			$stats=array();
+			foreach($command->queryAll() as $row)
+				$stats[$row['c']]=$row['s'];
+		}
+		else  // composite FK
+		{
+			$keys=array_keys($records);
+			foreach($keys as &$key)
+			{
+				$key2=unserialize($key);
+				$key=array();
+				foreach($pkTable->primaryKey as $pk)
+					$key[$map[$pk]]=$key2[$pk];
+			}
+			$cols=array();
+			foreach($pkTable->primaryKey as $n=>$pk)
+			{
+				$name=$table->columns[$map[$pk]]->rawName;
+				$cols[$name]=$name.' AS '.$schema->quoteColumnName('c'.$n);
+			}
+			$sql='SELECT '.implode(', ',$cols).", {$relation->select} AS $s FROM {$table->rawName}"
+				.$where
+				.' GROUP BY '.implode(', ',array_keys($cols)).$group
+				.' HAVING '.$builder->createInCondition($table,$fks,$keys)
+				.$having.$order;
+			$command=$builder->getDbConnection()->createCommand($sql);
+			if(is_array($relation->params))
+				$builder->bindValues($command,$relation->params);
+			$stats=array();
+			foreach($command->queryAll() as $row)
+			{
+				$key=array();
+				foreach($pkTable->primaryKey as $n=>$pk)
+					$key[$pk]=$row['c'.$n];
+				$stats[serialize($key)]=$row['s'];
+			}
+		}
+
+		// populate the results into existing records
+		foreach($records as $pk=>$record)
+			$record->addRelatedRecord($relation->name,isset($stats[$pk])?$stats[$pk]:$relation->defaultValue,false);
+	}
+
+	private function queryManyMany($joinTableName,$keys)
+	{
+		$relation=$this->relation;
+		$model=TActiveRecord::model($relation->className);
+		$table=$model->getTableSchema();
+		$builder=$model->getCommandBuilder();
+		$schema=$builder->getSchema();
+		$pkTable=$this->_parent->model->getTableSchema();
+
+		if(($joinTable=$builder->getSchema()->getTable($joinTableName))===null)
+			throw new TDbException('The relation "'.($relation->name).'" in active record class "'.get_class($this->_parent->model).'" is not specified correctly. The join table "'.$joinTableName.'" given in the foreign key cannot be found in the database.');
+
+		$fks=preg_split('/[\s,]+/',$keys,-1,PREG_SPLIT_NO_EMPTY);
+		if(count($fks)!==count($table->primaryKey)+count($pkTable->primaryKey))
+			throw new TDbException('The relation "'.($relation->name).'" in active record class "'.get_class($this->_parent->model).'" is specified with an incomplete foreign key. The foreign key must consist of columns referencing both joining tables.');
+
+		$joinCondition=array();
+		$map=array();
+		foreach($fks as $i=>$fk)
+		{
+			if(!isset($joinTable->columns[$fk]))
+				throw new TDbException('The relation "'.($relation->name).'" in active record class "'.get_class($this->_parent->model).'" is specified with an invalid foreign key "'.$fk.'". There is no such column in the table "'.($joinTable->name).'".');
+
+			if(isset($joinTable->foreignKeys[$fk]))
+			{
+				list($tableName,$pk)=$joinTable->foreignKeys[$fk];
+				if(!isset($joinCondition[$pk]) && $schema->compareTableNames($table->rawName,$tableName))
+					$joinCondition[$pk]=$table->rawName.'.'.$schema->quoteColumnName($pk).'='.$joinTable->rawName.'.'.$schema->quoteColumnName($fk);
+				else if(!isset($map[$pk]) && $schema->compareTableNames($pkTable->rawName,$tableName))
+					$map[$pk]=$fk;
+				else
+					throw new TDbException('The relation "'.($relation->name).'" in active record class "'.get_class($this->_parent->model).'" is specified with an invalid foreign key "'.$fk.'". The foreign key does not point to either joining table.');
+			}
+			else // FK constraints not defined
+			{
+				if($i<count($pkTable->primaryKey))
+				{
+					$pk=is_array($pkTable->primaryKey) ? $pkTable->primaryKey[$i] : $pkTable->primaryKey;
+					$map[$pk]=$fk;
+				}
+				else
+				{
+					$j=$i-count($pkTable->primaryKey);
+					$pk=is_array($table->primaryKey) ? $table->primaryKey[$j] : $table->primaryKey;
+					$joinCondition[$pk]=$table->rawName.'.'.$schema->quoteColumnName($pk).'='.$joinTable->rawName.'.'.$schema->quoteColumnName($fk);
+				}
+			}
+		}
+
+		if($joinCondition===array() || $map===array())
+			throw new TDbException('The relation "'.($relation->name).'" in active record class "'.get_class($this->_parent->model).'" is specified with an incomplete foreign key. The foreign key must consist of columns referencing both joining tables.');
+
+		$records=$this->_parent->records;
+
+		$cols=array();
+		foreach(is_string($pkTable->primaryKey)?array($pkTable->primaryKey):$pkTable->primaryKey as $n=>$pk)
+		{
+			$name=$joinTable->rawName.'.'.$schema->quoteColumnName($map[$pk]);
+			$cols[$name]=$name.' AS '.$schema->quoteColumnName('c'.$n);
+		}
+
+		$keys=array_keys($records);
+		if(is_array($pkTable->primaryKey))
+		{
+			foreach($keys as &$key)
+			{
+				$key2=unserialize($key);
+				$key=array();
+				foreach($pkTable->primaryKey as $pk)
+					$key[$map[$pk]]=$key2[$pk];
+			}
+		}
+
+		$where=empty($relation->condition)?'' : ' WHERE ('.$relation->condition.')';
+		$group=empty($relation->group)?'' : ', '.$relation->group;
+		$having=empty($relation->having)?'' : ' AND ('.$relation->having.')';
+		$order=empty($relation->order)?'' : ' ORDER BY '.$relation->order;
+
+		$sql='SELECT '.$this->relation->select.' AS '.$schema->quoteColumnName('s').', '.implode(', ',$cols)
+			.' FROM '.$table->rawName.' INNER JOIN '.$joinTable->rawName
+			.' ON ('.implode(') AND (',$joinCondition).')'
+			.$where
+			.' GROUP BY '.implode(', ',array_keys($cols)).$group
+			.' HAVING ('.$builder->createInCondition($joinTable,$map,$keys).')'
+			.$having.$order;
+
+		$command=$builder->getDbConnection()->createCommand($sql);
+		if(is_array($relation->params))
+			$builder->bindValues($command,$relation->params);
+
+		$stats=array();
+		foreach($command->queryAll() as $row)
+		{
+			if(is_array($pkTable->primaryKey))
+			{
+				$key=array();
+				foreach($pkTable->primaryKey as $n=>$k)
+					$key[$k]=$row['c'.$n];
+				$stats[serialize($key)]=$row['s'];
+			}
+			else
+				$stats[$row['c0']]=$row['s'];
+		}
+
+		foreach($records as $pk=>$record)
+			$record->addRelatedRecord($relation->name,isset($stats[$pk])?$stats[$pk]:$this->relation->defaultValue,false);
+	}
+}
diff --git a/framework/Db/ActiveRecord/TActiveRecord.php b/framework/Db/ActiveRecord/TActiveRecord.php
new file mode 100644
index 00000000..c0ffc32e
--- /dev/null
+++ b/framework/Db/ActiveRecord/TActiveRecord.php
@@ -0,0 +1,1843 @@
+<?php
+/**
+ * CActiveRecord class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+/**
+ * CActiveRecord is the base class for classes representing relational data.
+ *
+ * It implements the active record design pattern, a popular Object-Relational Mapping (ORM) technique.
+ * Please check {@link http://www.yiiframework.com/doc/guide/database.ar the Guide} for more details
+ * about this class.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+
+Prado::using('System.Base.TModel');
+Prado::using('System.Db.*');
+Prado::using('System.Db.ActiveRecord.*');
+Prado::using('System.Base.TEvent');
+Prado::using('System.Db.ActiveRecord.TActiveRecordCriteria');
+
+abstract class TActiveRecord extends TModel
+{
+	const BELONGS_TO='TBelongsToRelation';
+	const HAS_ONE='THasOneRelation';
+	const HAS_MANY='THasManyRelation';
+	const MANY_MANY='TManyManyRelation';
+	const STAT='TStatRelation';
+
+	/**
+	 * @var CDbConnection the default database connection for all active record classes.
+	 * By default, this is the 'db' application component.
+	 * @see getDbConnection
+	 */
+	public static $db;
+
+	private static $_models=array();			// class name => model
+
+	private $_md;								// meta data
+	private $_new=false;						// whether this instance is new or not
+	private $_attributes=array();				// attribute name => attribute value
+	private $_related=array();					// attribute name => related objects
+	private $_c;								// query criteria (used by finder only)
+
+	/**
+	 * Returns the instance of a active record finder for a particular class.
+	 * The finder objects are static instances for each ActiveRecord class.
+	 * This means that event handlers bound to these finder instances are class wide.
+	 * Create a new instance of the ActiveRecord class if you wish to bound the
+	 * event handlers to object instance.
+	 * @param string active record class name.
+	 * @return TActiveRecord active record finder instance.
+	 */
+ 
+	/**
+	 * Constructor.
+	 * @param string scenario name. See {@link CModel::scenario} for more details about this parameter.
+	 */
+	public function __construct($scenario='insert')
+	{
+		if($scenario===null) // internally used by populateRecord() and model()
+			return;
+
+		$this->setScenario($scenario);
+		$this->setIsNewRecord(true);
+		$this->_attributes=$this->getMetaData()->attributeDefaults;
+
+		$this->attachBehaviors($this->behaviors());
+		$this->afterConstruct();
+	}
+
+	/**
+	 * PHP sleep magic method.
+	 * This method ensures that the model meta data reference is set to null.
+	 */
+	public function __sleep()
+	{
+		$this->_md=null;
+		return array_keys((array)$this);
+	}
+
+	/**
+	 * PHP getter magic method.
+	 * This method is overridden so that AR attributes can be accessed like properties.
+	 * @param string property name
+	 * @return mixed property value
+	 * @see getAttribute
+	 */
+	public function __get($name)
+	{
+		if(isset($this->_attributes[$name]))
+			return $this->_attributes[$name];
+		else if(isset($this->getMetaData()->columns[$name]))
+			return null;
+		else if(isset($this->_related[$name]))
+			return $this->_related[$name];
+		else if(isset($this->getMetaData()->relations[$name]))
+			return $this->getRelated($name);
+		else
+			return parent::__get($name);
+	}
+
+	/**
+	 * PHP setter magic method.
+	 * This method is overridden so that AR attributes can be accessed like properties.
+	 * @param string property name
+	 * @param mixed property value
+	 */
+	public function __set($name,$value)
+	{
+		if($this->setAttribute($name,$value)===false)
+			parent::__set($name,$value);
+	}
+
+	/**
+	 * Checks if a property value is null.
+	 * This method overrides the parent implementation by checking
+	 * if the named attribute is null or not.
+	 * @param string the property name or the event name
+	 * @return boolean whether the property value is null
+	 * @since 1.0.1
+	 */
+	public function __isset($name)
+	{
+		if(isset($this->_attributes[$name]))
+			return true;
+		else if(isset($this->getMetaData()->columns[$name]))
+			return false;
+		else if(isset($this->_related[$name]))
+			return true;
+		else if(isset($this->getMetaData()->relations[$name]))
+			return $this->getRelated($name)!==null;
+#		else
+#			return parent::__isset($name);
+	}
+
+	/**
+	 * Sets a component property to be null.
+	 * This method overrides the parent implementation by clearing
+	 * the specified attribute value.
+	 * @param string the property name or the event name
+	 * @since 1.0.1
+	 */
+	public function __unset($name)
+	{
+		if(isset($this->getMetaData()->columns[$name]))
+			unset($this->_attributes[$name]);
+		else if(isset($this->getMetaData()->relations[$name]))
+			unset($this->_related[$name]);
+		else
+			parent::__unset($name);
+	}
+
+	/**
+	 * Calls the named method which is not a class method.
+	 * Do not call this method. This is a PHP magic method that we override
+	 * to implement the named scope feature.
+	 * @param string the method name
+	 * @param array method parameters
+	 * @return mixed the method return value
+	 * @since 1.0.5
+	 * 
+	 * @TODO: implement __call to parent
+	 * 
+	 */
+	public function __call($name,$parameters)
+	{
+		if(isset($this->getMetaData()->relations[$name]))
+		{
+			if(empty($parameters))
+				return $this->getRelated($name,false);
+			else
+				return $this->getRelated($name,false,$parameters[0]);
+		}
+
+		$scopes=$this->scopes();
+		if(isset($scopes[$name]))
+		{
+			$this->getDbCriteria()->mergeWith($scopes[$name]);
+			return $this;
+		}
+
+# 		return parent::__call($name,$parameters);*/
+	}
+
+	/**
+	 * Returns the related record(s).
+	 * This method will return the related record(s) of the current record.
+	 * If the relation is HAS_ONE or BELONGS_TO, it will return a single object
+	 * or null if the object does not exist.
+	 * If the relation is HAS_MANY or MANY_MANY, it will return an array of objects
+	 * or an empty array.
+	 * @param string the relation name (see {@link relations})
+	 * @param boolean whether to reload the related objects from database. Defaults to false.
+	 * @param array additional parameters that customize the query conditions as specified in the relation declaration.
+	 * This parameter has been available since version 1.0.5.
+	 * @return mixed the related object(s).
+	 * @throws CDbException if the relation is not specified in {@link relations}.
+	 * @since 1.0.2
+	 */
+	public function getRelated($name,$refresh=false,$params=array())
+	{
+		if(!$refresh && $params===array() && (isset($this->_related[$name]) || array_key_exists($name,$this->_related)))
+			return $this->_related[$name];
+
+		$md=$this->getMetaData();
+		if(!isset($md->relations[$name]))
+			throw new TDbException(get_class($this).' does not have relation "'.$name.'".');
+
+		Prado::trace('lazy loading '.get_class($this).'.'.$name,'System.Db.ActiveRecord.TActiveRecord');
+		$relation=$md->relations[$name];
+		if($this->getIsNewRecord() && ($relation instanceof THasOneRelation || $relation instanceof THasManyRelation))
+			return $relation instanceof THasOneRelation ? null : array();
+
+		if($params!==array()) // dynamic query
+		{
+			$exists=isset($this->_related[$name]) || array_key_exists($name,$this->_related);
+			if($exists)
+				$save=$this->_related[$name];
+			unset($this->_related[$name]);
+			$r=array($name=>$params);
+		}
+		else
+			$r=$name;
+
+		$finder=new TActiveFinder($this,$r);
+		$finder->lazyFind($this);
+
+		if(!isset($this->_related[$name]))
+		{
+			if($relation instanceof THasManyRelation)
+				$this->_related[$name]=array();
+			else if($relation instanceof TStatRelation)
+				$this->_related[$name]=$relation->defaultValue;
+			else
+				$this->_related[$name]=null;
+		}
+
+		if($params!==array())
+		{
+			$results=$this->_related[$name];
+			if($exists)
+				$this->_related[$name]=$save;
+			else
+				unset($this->_related[$name]);
+			return $results;
+		}
+		else
+			return $this->_related[$name];
+	}
+
+	/**
+	 * Returns a value indicating whether the named related object(s) has been loaded.
+	 * @param string the relation name
+	 * @return booolean a value indicating whether the named related object(s) has been loaded.
+	 * @since 1.0.3
+	 */
+	public function hasRelated($name)
+	{
+		return isset($this->_related[$name]) || array_key_exists($name,$this->_related);
+	}
+
+	/**
+	 * Returns the query criteria associated with this model.
+	 * @param boolean whether to create a criteria instance if it does not exist. Defaults to true.
+	 * @return CDbCriteria the query criteria that is associated with this model.
+	 * This criteria is mainly used by {@link scopes named scope} feature to accumulate
+	 * different criteria specifications.
+	 * @since 1.0.5
+	 */
+	public function getDbCriteria($createIfNull=true)
+	{
+		if($this->_c===null)
+		{
+			if(($c=$this->defaultScope())!==array() || $createIfNull)
+				$this->_c=new TDbCriteria($c);
+		}
+		return $this->_c;
+	}
+
+	/**
+	 * Returns the default named scope that should be applied to all queries implicitly for this model.
+	 * The default implementation simply returns an empty array. You may override this method
+	 * if the model needs to be queried with some default criteria (e.g. only active records should be returned).
+	 * @return array the query criteria. This will be used as the parameter to the constructor
+	 * of {@link CDbCriteria}.
+	 * @since 1.0.5
+	 */
+	public function defaultScope()
+	{
+		return array();
+	}
+
+	/**
+	 * Returns the static model of the specified AR class.
+	 * The model returned is a static instance of the AR class.
+	 * It is provided for invoking class-level methods (something similar to static class methods.)
+	 *
+	 * EVERY derived AR class must override this method as follows,
+	 * <pre>
+	 * public static function model($className=__CLASS__)
+	 * {
+	 *     return parent::model($className);
+	 * }
+	 * </pre>
+	 *
+	 * @param string active record class name.
+	 * @return CActiveRecord active record model instance.
+	 */
+	public static function model($className=__CLASS__)
+	{
+		if(isset(self::$_models[$className]))
+			return self::$_models[$className];
+		else
+		{
+			$model=self::$_models[$className]=new $className(null);
+			$model->attachBehaviors($model->behaviors());
+			$model->_md=new TActiveRecordMetaData($model);
+			return $model;
+		}
+	}
+
+	/**
+	 * @return CActiveRecordMetaData the meta for this AR class.
+	 */
+	public function getMetaData()
+	{
+		if($this->_md!==null)
+			return $this->_md;
+		else
+			return $this->_md=self::model(get_class($this))->_md;
+	}
+
+	/**
+	 * Returns the name of the associated database table.
+	 * By default this method returns the class name as the table name.
+	 * You may override this method if the table is not named after this convention.
+	 * @return string the table name
+	 */
+	public function tableName()
+	{
+		return get_class($this);
+	}
+
+	/**
+	 * Returns the primary key of the associated database table.
+	 * This method is meant to be overridden in case when the table is not defined with a primary key
+	 * (for some legency database). If the table is already defined with a primary key,
+	 * you do not need to override this method. The default implementation simply returns null,
+	 * meaning using the primary key defined in the database.
+	 * @return mixed the primary key of the associated database table.
+	 * If the key is a single column, it should return the column name;
+	 * If the key is a composite one consisting of several columns, it should
+	 * return the array of the key column names.
+	 * @since 1.0.4
+	 */
+	public function primaryKey()
+	{
+	}
+
+	/**
+	 * This method should be overridden to declare related objects.
+	 *
+	 * There are four types of relations that may exist between two active record objects:
+	 * <ul>
+	 * <li>BELONGS_TO: e.g. a member belongs to a team;</li>
+	 * <li>HAS_ONE: e.g. a member has at most one profile;</li>
+	 * <li>HAS_MANY: e.g. a team has many members;</li>
+	 * <li>MANY_MANY: e.g. a member has many skills and a skill belongs to a member.</li>
+	 * </ul>
+	 *
+	 * By declaring these relations, CActiveRecord can bring back related objects
+	 * in either lazy loading or eager loading approach, and you save the effort of
+	 * writing complex JOIN SQL statements.
+	 *
+	 * Each kind of related objects is defined in this method as an array with the following elements:
+	 * <pre>
+	 * 'varName'=>array('relationType', 'className', 'foreignKey', ...additional options)
+	 * </pre>
+	 * where 'varName' refers to the name of the variable/property that the related object(s) can
+	 * be accessed through; 'relationType' refers to the type of the relation, which can be one of the
+	 * following four constants: self::BELONGS_TO, self::HAS_ONE, self::HAS_MANY and self::MANY_MANY;
+	 * 'className' refers to the name of the active record class that the related object(s) is of;
+	 * and 'foreignKey' states the foreign key that relates the two kinds of active record.
+	 * Note, for composite foreign keys, they must be listed together, separating with space or comma;
+	 * and for foreign keys used in MANY_MANY relation, the joining table must be declared as well
+	 * (e.g. 'joinTable(fk1, fk2)').
+	 *
+	 * Additional options may be specified as name-value pairs in the rest array elements:
+	 * <ul>
+	 * <li>'select': string|array, a list of columns to be selected. Defaults to '*', meaning all columns.
+	 *   Column names should be disambiguated if they appear in an expression (e.g. COUNT(??.name) AS name_count).</li>
+	 * <li>'condition': string, the WHERE clause. Defaults to empty. Note, column references need to
+	 *   be disambiguated with prefix '??.' (e.g. ??.age&gt;20)</li>
+	 * <li>'order': string, the ORDER BY clause. Defaults to empty. Note, column references need to
+	 *   be disambiguated with prefix '??.' (e.g. ??.age DESC)</li>
+	 * <li>'with': string|array, a list of child related objects that should be loaded together with this object.
+	 *   Note, this is only honored by lazy loading, not eager loading.</li>
+	 * <li>'joinType': type of join. Defaults to 'LEFT OUTER JOIN'.</li>
+	 * <li>'alias': the alias for the table associated with this relationship.
+	 *   This option has been available since version 1.0.1. It defaults to null,
+	 *   meaning the table alias is the same as the relation name.</li>
+     * <li>'params': the parameters to be bound to the generated SQL statement.
+	 *   This should be given as an array of name-value pairs. This option has been
+	 *   available since version 1.0.3.</li>
+	 * <li>'on': the ON clause. The condition specified here will be appended
+	 *   to the joining condition using the AND operator. This option has been
+	 *   available since version 1.0.2.</li>
+	 * </ul>
+	 *
+	 * The following options are available for certain relations when lazy loading:
+	 * <ul>
+	 * <li>'group': string, the GROUP BY clause. Defaults to empty. Note, column references need to
+	 *   be disambiguated with prefix '??.' (e.g. ??.age). This option only applies to HAS_MANY and MANY_MANY relations.</li>
+	 * <li>'having': string, the HAVING clause. Defaults to empty. Note, column references need to
+	 *   be disambiguated with prefix '??.' (e.g. ??.age). This option only applies to HAS_MANY and MANY_MANY relations.</li>
+	 * <li>'limit': limit of the rows to be selected. This option does not apply to BELONGS_TO relation.</li>
+	 * <li>'offset': offset of the rows to be selected. This option does not apply to BELONGS_TO relation.</li>
+	 * </ul>
+	 *
+	 * Below is an example declaring related objects for 'Post' active record class:
+	 * <pre>
+	 * return array(
+	 *     'author'=>array(self::BELONGS_TO, 'User', 'authorID'),
+	 *     'comments'=>array(self::HAS_MANY, 'Comment', 'postID', 'with'=>'author', 'order'=>'createTime DESC'),
+	 *     'tags'=>array(self::MANY_MANY, 'Tag', 'PostTag(postID, tagID)', 'order'=>'name'),
+	 * );
+	 * </pre>
+	 *
+	 * @return array list of related object declarations. Defaults to empty array.
+	 */
+	public function relations()
+	{
+		return array();
+	}
+	
+	/**
+	 * Returns the declaration of named scopes.
+	 * A named scope represents a query criteria that can be chained together with
+	 * other named scopes and applied to a query. This method should be overridden
+	 * by child classes to declare named scopes for the particular AR classes.
+	 * For example, the following code declares two named scopes: 'recently' and
+	 * 'published'.
+	 * <pre>
+	 * return array(
+	 *     'published'=>array(
+	 *           'condition'=>'status=1',
+	 *     ),
+	 *     'recently'=>array(
+	 *           'order'=>'createTime DESC',
+	 *           'limit'=>5,
+	 *     ),
+	 * );
+	 * </pre>
+	 * If the above scopes are declared in a 'Post' model, we can perform the following
+	 * queries:
+	 * <pre>
+	 * $posts=Post::model()->published()->findAll();
+	 * $posts=Post::model()->published()->recently()->findAll();
+	 * $posts=Post::model()->published()->with('comments')->findAll();
+	 * </pre>
+	 * Note that the last query is a relational query.
+	 *
+	 * @return array the scope definition. The array keys are scope names; the array
+	 * values are the corresponding scope definitions. Each scope definition is represented
+	 * as an array whose keys must be properties of {@link CDbCriteria}.
+	 * @since 1.0.5
+	 */
+	public function scopes()
+	{
+		return array();
+	}
+
+	/**
+	 * Returns the list of all attribute names of the model.
+	 * This would return all column names of the table associated with this AR class.
+	 * @return array list of attribute names.
+	 * @since 1.0.1
+	 */
+	public function attributeNames()
+	{
+		return array_keys($this->getMetaData()->columns);
+	}
+
+	/**
+	 * Returns the database connection used by active record.
+	 * By default, the "db" application component is used as the database connection.
+	 * You may override this method if you want to use a different database connection.
+	 * @return CDbConnection the database connection used by active record.
+	 * 
+	 * @TODO Get default db connection if theres none set
+	 * 
+	 */
+	public function getDbConnection()
+	{
+		if(self::$db!==null)
+			return self::$db;
+		else
+		{
+			self::$db=Prado::getApplication()->getModule($this->getConnectionId())->getDbConnection();
+			if(self::$db instanceof TDbConnection)
+			{
+				self::$db->setActive(true);
+				return self::$db;
+			}
+			else
+				throw new TDbException('ActiveRecord requires a db connection.');
+		}
+	}
+
+	/**
+	 * Returns connection id (must be overloaded by child classes)
+	 * @return string Id of TDbConnection module
+	 */
+	abstract public function getConnectionId();
+
+	/**
+	 * @param string the relation name
+	 * @return CActiveRelation the named relation declared for this AR class. Null if the relation does not exist.
+	 */
+	public function getActiveRelation($name)
+	{
+		return isset($this->getMetaData()->relations[$name]) ? $this->getMetaData()->relations[$name] : null;
+	}
+
+	/**
+	 * @return CDbTableSchema the metadata of the table that this AR belongs to
+	 */
+	public function getTableSchema()
+	{
+		return $this->getMetaData()->tableSchema;
+	}
+
+	/**
+	 * @return CDbCommandBuilder the command builder used by this AR
+	 */
+	public function getCommandBuilder()
+	{
+		return $this->getDbConnection()->getSchema()->getCommandBuilder();
+	}
+
+	/**
+	 * @param string attribute name
+	 * @return boolean whether this AR has the named attribute (table column).
+	 */
+	public function hasAttribute($name)
+	{
+		return isset($this->getMetaData()->columns[$name]);
+	}
+
+	/**
+	 * Returns the named attribute value.
+	 * If this is a new record and the attribute is not set before,
+	 * the default column value will be returned.
+	 * If this record is the result of a query and the attribute is not loaded,
+	 * null will be returned.
+	 * You may also use $this->AttributeName to obtain the attribute value.
+	 * @param string the attribute name
+	 * @return mixed the attribute value. Null if the attribute is not set or does not exist.
+	 * @see hasAttribute
+	 */
+	public function getAttribute($name)
+	{
+		if(property_exists($this,$name))
+			return $this->$name;
+		else if(isset($this->_attributes[$name]))
+			return $this->_attributes[$name];
+	}
+
+	/**
+	 * Sets the named attribute value.
+	 * You may also use $this->AttributeName to set the attribute value.
+	 * @param string the attribute name
+	 * @param mixed the attribute value.
+	 * @return boolean whether the attribute exists and the assignment is conducted successfully
+	 * @see hasAttribute
+	 */
+	public function setAttribute($name,$value)
+	{
+		if(property_exists($this,$name))
+			$this->$name=$value;
+		else if(isset($this->getMetaData()->columns[$name]))
+			$this->_attributes[$name]=$value;
+		else
+			return false;
+		return true;
+	}
+
+	/**
+	 * Adds a related object to this record.
+	 * This method is used internally by {@link CActiveFinder} to populate related objects.
+	 * @param string attribute name
+	 * @param mixed the related record
+	 * @param boolean whether the relation is HAS_MANY/MANY_MANY.
+	 */
+	public function addRelatedRecord($name,$record,$multiple)
+	{
+		if($multiple)
+		{
+			if(!isset($this->_related[$name]))
+				$this->_related[$name]=array();
+			if($record instanceof TActiveRecord)
+				$this->_related[$name][]=$record;
+		}
+		else if(!isset($this->_related[$name]))
+			$this->_related[$name]=$record;
+	}
+
+	/**
+	 * Returns all column attribute values.
+	 * Note, related objects are not returned.
+	 * @param mixed names of attributes whose value needs to be returned.
+	 * If this is true (default), then all attribute values will be returned, including
+	 * those that are not loaded from DB (null will be returned for those attributes).
+	 * If this is null, all attributes except those that are not loaded from DB will be returned.
+	 * @return array attribute values indexed by attribute names.
+	 */
+	public function getAttributes($names=true)
+	{
+		$attributes=$this->_attributes;
+		foreach($this->getMetaData()->columns as $name=>$column)
+		{
+			if(property_exists($this,$name))
+				$attributes[$name]=$this->$name;
+			else if($names===true && !isset($attributes[$name]))
+				$attributes[$name]=null;
+		}
+		if(is_array($names))
+		{
+			$attrs=array();
+			foreach($names as $name)
+				$attrs[$name]=isset($attributes[$name])?$attributes[$name]:null;
+			return $attrs;
+		}
+		else
+			return $attributes;
+	}
+
+	/**
+	 * Saves the current record.
+	 *
+	 * The record is inserted as a row into the database table if its {@link isNewRecord}
+	 * property is true (usually the case when the record is created using the 'new'
+	 * operator). Otherwise, it will be used to update the corresponding row in the table
+	 * (usually the case if the record is obtained using one of those 'find' methods.)
+	 *
+	 * Validation will be performed before saving the record. If the validation fails,
+	 * the record will not be saved. You can call {@link getErrors()} to retrieve the
+	 * validation errors.
+	 *
+	 * If the record is saved via insertion, its {@link isNewRecord} property will be
+	 * set false, and its {@link scenario} property will be set to be 'update'.
+	 * And if its primary key is auto-incremental and is not set before insertion,
+	 * the primary key will be populated with the automatically generated key value.
+	 *
+	 * @param boolean whether to perform validation before saving the record.
+	 * If the validation fails, the record will not be saved to database.
+	 * @param array list of attributes that need to be saved. Defaults to null,
+	 * meaning all attributes that are loaded from DB will be saved.
+	 * @return boolean whether the saving succeeds
+	 */
+	public function save($runValidation=true,$attributes=null)
+	{
+		if(!$runValidation || $this->validate($attributes))
+			return $this->getIsNewRecord() ? $this->insert($attributes) : $this->update($attributes);
+		else
+			return false;
+	}
+
+	/**
+	 * @return boolean whether the record is new and should be inserted when calling {@link save}.
+	 * This property is automatically set in constructor and {@link populateRecord}.
+	 * Defaults to false, but it will be set to true if the instance is created using
+	 * the new operator.
+	 */
+	public function getIsNewRecord()
+	{
+		return $this->_new;
+	}
+
+	/**
+	 * @param boolean whether the record is new and should be inserted when calling {@link save}.
+	 * @see getIsNewRecord
+	 */
+	public function setIsNewRecord($value)
+	{
+		$this->_new=$value;
+	}
+
+	/**
+	 * This event is raised before the record is saved.
+	 * @param CEvent the event parameter
+	 * @since 1.0.2
+	 */
+	public function onBeforeSave($event)
+	{
+		$this->raiseEvent('onBeforeSave',$event);
+	}
+
+	/**
+	 * This event is raised after the record is saved.
+	 * @param CEvent the event parameter
+	 * @since 1.0.2
+	 */
+	public function onAfterSave($event)
+	{
+		$this->raiseEvent('onAfterSave',$event);
+	}
+
+	/**
+	 * This event is raised before the record is deleted.
+	 * @param CEvent the event parameter
+	 * @since 1.0.2
+	 */
+	public function onBeforeDelete($event)
+	{
+		$this->raiseEvent('onBeforeDelete',$event);
+	}
+
+	/**
+	 * This event is raised after the record is deleted.
+	 * @param CEvent the event parameter
+	 * @since 1.0.2
+	 */
+	public function onAfterDelete($event)
+	{
+		$this->raiseEvent('onAfterDelete',$event);
+	}
+
+	/**
+	 * This event is raised after the record instance is created by new operator.
+	 * @param CEvent the event parameter
+	 * @since 1.0.2
+	 */
+	public function onAfterConstruct($event)
+	{
+		$this->raiseEvent('onAfterConstruct',$event);
+	}
+
+	/**
+	 * This event is raised after the record is instantiated by a find method.
+	 * @param CEvent the event parameter
+	 * @since 1.0.2
+	 */
+	public function onAfterFind($event)
+	{
+		$this->raiseEvent('onAfterFind',$event);
+	}
+
+	/**
+	 * This method is invoked before saving a record (after validation, if any).
+	 * The default implementation raises the {@link onBeforeSave} event.
+	 * You may override this method to do any preparation work for record saving.
+	 * Use {@link isNewRecord} to determine whether the saving is
+	 * for inserting or updating record.
+	 * Make sure you call the parent implementation so that the event is raised properly.
+	 * @return boolean whether the saving should be executed. Defaults to true.
+	 */
+	protected function beforeSave()
+	{
+		$this->onBeforeSave(new TEvent($this));
+		return true;
+	}
+
+	/**
+	 * This method is invoked after saving a record.
+	 * The default implementation raises the {@link onAfterSave} event.
+	 * You may override this method to do postprocessing after record saving.
+	 * Make sure you call the parent implementation so that the event is raised properly.
+	 */
+	protected function afterSave()
+	{
+		$this->onAfterSave(new TEvent($this));
+	}
+
+	/**
+	 * This method is invoked before deleting a record.
+	 * The default implementation raises the {@link onBeforeDelete} event.
+	 * You may override this method to do any preparation work for record deletion.
+	 * Make sure you call the parent implementation so that the event is raised properly.
+	 * @return boolean whether the record should be deleted. Defaults to true.
+	 */
+	protected function beforeDelete()
+	{
+		$this->onBeforeDelete(new TEvent($this));
+		return true;
+	}
+
+	/**
+	 * This method is invoked after deleting a record.
+	 * The default implementation raises the {@link onAfterDelete} event.
+	 * You may override this method to do postprocessing after the record is deleted.
+	 * Make sure you call the parent implementation so that the event is raised properly.
+	 */
+	protected function afterDelete()
+	{
+		$this->onAfterDelete(new TEvent($this));
+	}
+
+	/**
+	 * This method is invoked after a record instance is created by new operator.
+	 * The default implementation raises the {@link onAfterConstruct} event.
+	 * You may override this method to do postprocessing after record creation.
+	 * Make sure you call the parent implementation so that the event is raised properly.
+	 */
+	protected function afterConstruct()
+	{
+		$this->onAfterConstruct(new TEvent($this));
+	}
+
+	/**
+	 * This method is invoked after each record is instantiated by a find method.
+	 * The default implementation raises the {@link onAfterFind} event.
+	 * You may override this method to do postprocessing after each newly found record is instantiated.
+	 * Make sure you call the parent implementation so that the event is raised properly.
+	 */
+	protected function afterFind()
+	{
+		$this->onAfterFind(new TEvent($this));
+	}
+
+	/**
+	 * Calls {@link afterFind}.
+	 * This method is internally used.
+	 * @since 1.0.3
+	 */
+	public function afterFindInternal()
+	{
+		$this->afterFind();
+	}
+
+	/**
+	 * Inserts a row into the table based on this active record attributes.
+	 * If the table's primary key is auto-incremental and is null before insertion,
+	 * it will be populated with the actual value after insertion.
+	 * Note, validation is not performed in this method. You may call {@link validate} to perform the validation.
+	 * After the record is inserted to DB successfully, its {@link isNewRecord} property will be set false,
+	 * and its {@link scenario} property will be set to be 'update'.
+	 * @param array list of attributes that need to be saved. Defaults to null,
+	 * meaning all attributes that are loaded from DB will be saved.
+	 * @return boolean whether the attributes are valid and the record is inserted successfully.
+	 * @throws CException if the record is not new
+	 */
+	public function insert($attributes=null)
+	{
+		if(!$this->getIsNewRecord())
+			throw new TDbException('The active record cannot be inserted to database because it is not new.');
+		if($this->beforeSave())
+		{
+			Prado::trace(get_class($this).'.insert()','System.Db.ActiveRecord.TActiveRecord');
+			$builder=$this->getCommandBuilder();
+			$table=$this->getMetaData()->tableSchema;
+			$command=$builder->createInsertCommand($table,$this->getAttributes($attributes));
+			if($command->execute())
+			{
+				$primaryKey=$table->primaryKey;
+				if($table->sequenceName!==null)
+				{
+					if(is_string($primaryKey) && $this->$primaryKey===null)
+						$this->$primaryKey=$builder->getLastInsertID($table);
+					else if(is_array($primaryKey))
+					{
+						foreach($primaryKey as $pk)
+						{
+							if($this->$pk===null)
+							{
+								$this->$pk=$builder->getLastInsertID($table);
+								break;
+							}
+						}
+					}
+				}
+				$this->afterSave();
+				$this->setIsNewRecord(false);
+				$this->setScenario('update');
+				return true;
+			}
+			else
+				$this->afterSave();
+		}
+		else
+			return false;
+	}
+
+	/**
+	 * Updates the row represented by this active record.
+	 * All loaded attributes will be saved to the database.
+	 * Note, validation is not performed in this method. You may call {@link validate} to perform the validation.
+	 * @param array list of attributes that need to be saved. Defaults to null,
+	 * meaning all attributes that are loaded from DB will be saved.
+	 * @return boolean whether the update is successful
+	 * @throws CException if the record is new
+	 */
+	public function update($attributes=null)
+	{
+		if($this->getIsNewRecord())
+			throw new TDbException('The active record cannot be updated because it is new.');
+		if($this->beforeSave())
+		{
+			Prado::trace(get_class($this).'.update()','System.Db.ActiveRecord.TActiveRecord');
+			$this->updateByPk($this->getPrimaryKey(),$this->getAttributes($attributes));
+			$this->afterSave();
+			return true;
+		}
+		else
+			return false;
+	}
+
+	/**
+	 * Saves a selected list of attributes.
+	 * Unlike {@link save}, this method only saves the specified attributes
+	 * of an existing row dataset. It thus has better performance.
+	 * Note, this method does neither attribute filtering nor validation.
+	 * So do not use this method with untrusted data (such as user posted data).
+	 * You may consider the following alternative if you want to do so:
+	 * <pre>
+	 * $postRecord=Post::model()->findByPk($postID);
+	 * $postRecord->attributes=$_POST['post'];
+	 * $postRecord->save();
+	 * </pre>
+	 * @param array attributes to be updated. Each element represents an attribute name
+	 * or an attribute value indexed by its name. If the latter, the record's
+	 * attribute will be changed accordingly before saving.
+	 * @return boolean whether the update is successful
+	 * @throws CException if the record is new or any database error
+	 */
+	public function saveAttributes($attributes)
+	{
+		if(!$this->getIsNewRecord())
+		{
+			Prado::trace(get_class($this).'.saveAttributes()','System.Db.ActiveRecord.TActiveRecord');
+			$values=array();
+			foreach($attributes as $name=>$value)
+			{
+				if(is_integer($name))
+					$values[$value]=$this->$value;
+				else
+					$values[$name]=$this->$name=$value;
+			}
+			return $this->updateByPk($this->getPrimaryKey(),$values)>0;
+		}
+		else
+			throw new TDbException('The active record cannot be updated because it is new.');
+	}
+
+	/**
+	 * Deletes the row corresponding to this active record.
+	 * @return boolean whether the deletion is successful.
+	 * @throws CException if the record is new
+	 */
+	public function delete()
+	{
+		if(!$this->getIsNewRecord())
+		{
+			Prado::trace(get_class($this).'.delete()','System.Db.ActiveRecord.TActiveRecord');
+			if($this->beforeDelete())
+			{
+				$result=$this->deleteByPk($this->getPrimaryKey())>0;
+				$this->afterDelete();
+				return $result;
+			}
+			else
+				return false;
+		}
+		else
+			throw new TDbException('The active record cannot be deleted because it is new.');
+	}
+
+	/**
+	 * Repopulates this active record with the latest data.
+	 * @return boolean whether the row still exists in the database. If true, the latest data will be populated to this active record.
+	 */
+	public function refresh()
+	{
+		Prado::trace(get_class($this).'.refresh()','System.Db.ActiveRecord.TActiveRecord');
+		if(!$this->getIsNewRecord() && ($record=$this->findByPk($this->getPrimaryKey()))!==null)
+		{
+			$this->_attributes=array();
+			$this->_related=array();
+			foreach($this->getMetaData()->columns as $name=>$column)
+				$this->$name=$record->$name;
+			return true;
+		}
+		else
+			return false;
+	}
+
+	/**
+	 * Compares this active record with another one.
+	 * The comparison is made by comparing the primary key values of the two active records.
+	 * @return boolean whether the two active records refer to the same row in the database table.
+	 */
+	public function equals($record)
+	{
+		return $this->tableName()===$record->tableName() && $this->getPrimaryKey()===$record->getPrimaryKey();
+	}
+
+	/**
+	 * @return mixed the primary key value. An array (column name=>column value) is returned if the primary key is composite.
+	 * If primary key is not defined, null will be returned.
+	 */
+	public function getPrimaryKey()
+	{
+		$table=$this->getMetaData()->tableSchema;
+		if(is_string($table->primaryKey))
+			return $this->{$table->primaryKey};
+		else if(is_array($table->primaryKey))
+		{
+			$values=array();
+			foreach($table->primaryKey as $name)
+				$values[$name]=$this->$name;
+			return $values;
+		}
+		else
+			return null;
+	}
+
+	private function query($criteria,$all=false)
+	{
+		$this->applyScopes($criteria);
+		$command=$this->getCommandBuilder()->createFindCommand($this->getTableSchema(),$criteria);
+		return $all ? $this->populateRecords($command->queryAll()) : $this->populateRecord($command->queryRow());
+	}
+
+	private function applyScopes(&$criteria)
+	{
+		if(($c=$this->getDbCriteria(false))!==null)
+		{
+			$c->mergeWith($criteria);
+			$criteria=$c;
+			$this->_c=null;
+		}
+	}
+
+	/**
+	 * Finds a single active record with the specified condition.
+	 * @param mixed query condition or criteria.
+	 * If a string, it is treated as query condition (the WHERE clause);
+	 * If an array, it is treated as the initial values for constructing a {@link CDbCriteria} object;
+	 * Otherwise, it should be an instance of {@link CDbCriteria}.
+	 * @param array parameters to be bound to an SQL statement.
+	 * This is only used when the first parameter is a string (query condition).
+	 * In other cases, please use {@link CDbCriteria::params} to set parameters.
+	 * @return CActiveRecord the record found. Null if no record is found.
+	 */
+	public function find($condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.find()','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->getCommandBuilder()->createCriteria($condition,$params);
+		$criteria->limit=1;
+		return $this->query($criteria);
+	}
+
+	/**
+	 * Finds all active records satisfying the specified condition.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return array list of active records satisfying the specified condition. An empty array is returned if none is found.
+	 */
+	public function findAll($condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.findAll()','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->getCommandBuilder()->createCriteria($condition,$params);
+		return $this->query($criteria,true);
+	}
+
+	/**
+	 * Finds a single active record with the specified primary key.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param mixed primary key value(s). Use array for multiple primary keys. For composite key, each key value must be an array (column name=>column value).
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return CActiveRecord the record found. Null if none is found.
+	 */
+	public function findByPk($pk,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.findByPk()','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->getCommandBuilder()->createPkCriteria($this->getTableSchema(),$pk,$condition,$params);
+		$criteria->limit=1;
+		return $this->query($criteria);
+	}
+
+	/**
+	 * Finds all active records with the specified primary keys.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param mixed primary key value(s). Use array for multiple primary keys. For composite key, each key value must be an array (column name=>column value).
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return array the records found. An empty array is returned if none is found.
+	 */
+	public function findAllByPk($pk,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.findAllByPk()','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->getCommandBuilder()->createPkCriteria($this->getTableSchema(),$pk,$condition,$params);
+		return $this->query($criteria,true);
+	}
+
+	/**
+	 * Finds a single active record that has the specified attribute values.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param array list of attribute values (indexed by attribute names) that the active records should match.
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return CActiveRecord the record found. Null if none is found.
+	 */
+	public function findByAttributes($attributes,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.findByAttributes()','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->getCommandBuilder()->createColumnCriteria($this->getTableSchema(),$attributes,$condition,$params);
+		$criteria->limit=1;
+		return $this->query($criteria);
+	}
+
+	/**
+	 * Finds all active records that have the specified attribute values.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param array list of attribute values (indexed by attribute names) that the active records should match.
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return array the records found. An empty array is returned if none is found.
+	 */
+	public function findAllByAttributes($attributes,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.findAllByAttributes()','System.Db.ActiveRecord.TActiveRecord');
+		$criteria=$this->getCommandBuilder()->createColumnCriteria($this->getTableSchema(),$attributes,$condition,$params);
+		return $this->query($criteria,true);
+	}
+
+	/**
+	 * Finds a single active record with the specified SQL statement.
+	 * @param string the SQL statement
+	 * @param array parameters to be bound to the SQL statement
+	 * @return CActiveRecord the record found. Null if none is found.
+	 */
+	public function findBySql($sql,$params=array())
+	{
+		Prado::trace(get_class($this).'.findBySql()','System.Db.ActiveRecord.TActiveRecord');
+		$command=$this->getCommandBuilder()->createSqlCommand($sql,$params);
+		return $this->populateRecord($command->queryRow());
+	}
+
+	/**
+	 * Finds all active records using the specified SQL statement.
+	 * @param string the SQL statement
+	 * @param array parameters to be bound to the SQL statement
+	 * @return array the records found. An empty array is returned if none is found.
+	 */
+	public function findAllBySql($sql,$params=array())
+	{
+		Prado::trace(get_class($this).'.findAllBySql()','System.Db.ActiveRecord.TActiveRecord');
+		$command=$this->getCommandBuilder()->createSqlCommand($sql,$params);
+		return $this->populateRecords($command->queryAll());
+	}
+
+	/**
+	 * Finds the number of rows satisfying the specified query condition.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return integer the number of rows satisfying the specified query condition.
+	 */
+	public function count($condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.count()','System.Db.ActiveRecord.TActiveRecord');
+		$builder=$this->getCommandBuilder();
+		$criteria=$builder->createCriteria($condition,$params);
+		$this->applyScopes($criteria);
+		return $builder->createCountCommand($this->getTableSchema(),$criteria)->queryScalar();
+	}
+
+	/**
+	 * Finds the number of rows using the given SQL statement.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param string the SQL statement
+	 * @param array parameters to be bound to the SQL statement
+	 * @return integer the number of rows using the given SQL statement.
+	 */
+	public function countBySql($sql,$params=array())
+	{
+		Prado::trace(get_class($this).'.countBySql()','System.Db.ActiveRecord.TActiveRecord');
+		return $this->getCommandBuilder()->createSqlCommand($sql,$params)->queryScalar();
+	}
+
+	/**
+	 * Checks whether there is row satisfying the specified condition.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return boolean whether there is row satisfying the specified condition.
+	 */
+	public function exists($condition,$params=array())
+	{
+		Prado::trace(get_class($this).'.exists()','System.Db.ActiveRecord.TActiveRecord');
+		$builder=$this->getCommandBuilder();
+		$criteria=$builder->createCriteria($condition,$params);
+		$table=$this->getTableSchema();
+		$criteria->select=reset($table->columns)->rawName;
+		$criteria->limit=1;
+		$this->applyScopes($criteria);
+		return $builder->createFindCommand($table,$criteria)->queryRow()!==false;
+	}
+
+	/**
+	 * Specifies which related objects should be eagerly loaded.
+	 * This method takes variable number of parameters. Each parameter specifies
+	 * the name of a relation or child-relation. For example,
+	 * <pre>
+	 * // find all posts together with their author and comments
+	 * Post::model()->with('author','comments')->findAll();
+	 * // find all posts together with their author and the author's profile
+	 * Post::model()->with('author','author.profile')->findAll();
+	 * </pre>
+	 * The relations should be declared in {@link relations()}.
+	 *
+	 * By default, the options specified in {@link relations()} will be used
+	 * to do relational query. In order to customize the options on the fly,
+	 * we should pass an array parameter to the with() method. The array keys
+	 * are relation names, and the array values are the corresponding query options.
+	 * For example,
+	 * <pre>
+	 * Post::model()->with(array(
+	 *     'author'=>array('select'=>'id, name'),
+	 *     'comments'=>array('condition'=>'approved=1', 'order'=>'createTime'),
+	 * ))->findAll();
+	 * </pre>
+	 *
+	 * This method returns a {@link CActiveFinder} instance that provides
+	 * a set of find methods similar to that of CActiveRecord.
+	 *
+	 * Note, the possible parameters to this method have been changed since version 1.0.2.
+	 * Previously, it was not possible to specify on-th-fly query options,
+	 * and child-relations were specified as hierarchical arrays.
+	 *
+	 * @return CActiveFinder the active finder instance. If no parameter is passed in, the object itself will be returned.
+	 */
+	public function with()
+	{
+		if(func_num_args()>0)
+		{
+			$with=func_get_args();
+			if(is_array($with[0]))  // the parameter is given as an array
+				$with=$with[0];
+			$finder=new TActiveFinder($this,$with,$this->getDbCriteria(false));
+			$this->_c=null;
+			return $finder;
+		}
+		else
+			return $this;
+	}
+
+	/**
+	 * Updates records with the specified primary key(s).
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * Note, the attributes are not checked for safety and validation is NOT performed.
+	 * @param mixed primary key value(s). Use array for multiple primary keys. For composite key, each key value must be an array (column name=>column value).
+	 * @param array list of attributes (name=>$value) to be updated
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return integer the number of rows being updated
+	 */
+	public function updateByPk($pk,$attributes,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.updateByPk()','System.Db.ActiveRecord.TActiveRecord');
+		$builder=$this->getCommandBuilder();
+		$table=$this->getTableSchema();
+		$criteria=$builder->createPkCriteria($table,$pk,$condition,$params);
+		$this->applyScopes($criteria);
+		$command=$builder->createUpdateCommand($table,$attributes,$criteria);
+		return $command->execute();
+	}
+
+	/**
+	 * Updates records with the specified condition.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * Note, the attributes are not checked for safety and no validation is done.
+	 * @param array list of attributes (name=>$value) to be updated
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return integer the number of rows being updated
+	 */
+	public function updateAll($attributes,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.updateAll()','System.Db.ActiveRecord.TActiveRecord');
+		$builder=$this->getCommandBuilder();
+		$criteria=$builder->createCriteria($condition,$params);
+		$this->applyScopes($criteria);
+		$command=$builder->createUpdateCommand($this->getTableSchema(),$attributes,$criteria);
+		return $command->execute();
+	}
+
+	/**
+	 * Updates one or several counter columns.
+	 * Note, this updates all rows of data unless a condition or criteria is specified.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param array the counters to be updated (column name=>increment value)
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return integer the number of rows being updated
+	 */
+	public function updateCounters($counters,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.updateCounters()','System.Db.ActiveRecord.TActiveRecord');
+		$builder=$this->getCommandBuilder();
+		$criteria=$builder->createCriteria($condition,$params);
+		$this->applyScopes($criteria);
+		$command=$builder->createUpdateCounterCommand($this->getTableSchema(),$counters,$criteria);
+		return $command->execute();
+	}
+
+	/**
+	 * Deletes rows with the specified primary key.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param mixed primary key value(s). Use array for multiple primary keys. For composite key, each key value must be an array (column name=>column value).
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return integer the number of rows deleted
+	 */
+	public function deleteByPk($pk,$condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.deleteByPk()','System.Db.ActiveRecord.TActiveRecord');
+		$builder=$this->getCommandBuilder();
+		$criteria=$builder->createPkCriteria($this->getTableSchema(),$pk,$condition,$params);
+		$this->applyScopes($criteria);
+		$command=$builder->createDeleteCommand($this->getTableSchema(),$criteria);
+		return $command->execute();
+	}
+
+	/**
+	 * Deletes rows with the specified condition.
+	 * See {@link find()} for detailed explanation about $condition and $params.
+	 * @param mixed query condition or criteria.
+	 * @param array parameters to be bound to an SQL statement.
+	 * @return integer the number of rows deleted
+	 */
+	public function deleteAll($condition='',$params=array())
+	{
+		Prado::trace(get_class($this).'.deleteAll()','System.Db.ActiveRecord.TActiveRecord');
+		$builder=$this->getCommandBuilder();
+		$criteria=$builder->createCriteria($condition,$params);
+		$this->applyScopes($criteria);
+		$command=$builder->createDeleteCommand($this->getTableSchema(),$criteria);
+		return $command->execute();
+	}
+
+	/**
+	 * Creates an active record with the given attributes.
+	 * This method is internally used by the find methods.
+	 * @param array attribute values (column name=>column value)
+	 * @param boolean whether to call {@link afterFind} after the record is populated.
+	 * This parameter is added in version 1.0.3.
+	 * @return CActiveRecord the newly created active record. The class of the object is the same as the model class.
+	 * Null is returned if the input data is false.
+	 */
+	public function populateRecord($attributes,$callAfterFind=true)
+	{
+		if($attributes!==false)
+		{
+			$record=$this->instantiate($attributes);
+			$record->_md=$this->getMetaData();
+			foreach($attributes as $name=>$value)
+			{
+				if(property_exists($record,$name))
+					$record->$name=$value;
+				else if(isset($record->_md->columns[$name]))
+					$record->_attributes[$name]=$value;
+			}
+			$record->attachBehaviors($record->behaviors());
+			if($callAfterFind)
+				$record->afterFind();
+			return $record;
+		}
+		else
+			return null;
+	}
+
+	/**
+	 * Creates a list of active records based on the input data.
+	 * This method is internally used by the find methods.
+	 * @param array list of attribute values for the active records.
+	 * @param boolean whether to call {@link afterFind} after each record is populated.
+	 * This parameter is added in version 1.0.3.
+	 * @return array list of active records.
+	 */
+	public function populateRecords($data,$callAfterFind=true)
+	{
+		$records=array();
+		$md=$this->getMetaData();
+		$table=$md->tableSchema;
+		foreach($data as $attributes)
+		{
+			$record=$this->instantiate($attributes);
+			$record->_md=$md;
+			foreach($attributes as $name=>$value)
+			{
+				if(property_exists($record,$name))
+					$record->$name=$value;
+				else if(isset($record->_md->columns[$name]))
+					$record->_attributes[$name]=$value;
+			}
+			$record->attachBehaviors($record->behaviors());
+			if($callAfterFind)
+				$record->afterFind();
+			$records[]=$record;
+		}
+		return $records;
+	}
+
+	/**
+	 * Creates an active record instance.
+	 * This method is called by {@link populateRecord} and {@link populateRecords}.
+	 * You may override this method if the instance being created
+	 * depends the attributes that are to be populated to the record.
+	 * For example, by creating a record based on the value of a column,
+	 * you may implement the so-called single-table inheritance mapping.
+	 * @param array list of attribute values for the active records.
+	 * @return CActiveRecord the active record
+	 * @since 1.0.2
+	 */
+	protected function instantiate($attributes)
+	{
+		$class=get_class($this);
+		$model=new $class(null);
+		$model->setScenario('update');
+		return $model;
+	}
+
+	/**
+	 * Returns whether there is an element at the specified offset.
+	 * This method is required by the interface ArrayAccess.
+	 * @param mixed the offset to check on
+	 * @return boolean
+	 * @since 1.0.2
+	 */
+	public function offsetExists($offset)
+	{
+		return isset($this->getMetaData()->columns[$offset]);
+	}
+}
+
+
+/**
+ * CBaseActiveRelation is the base class for all active relations.
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0.4
+ */
+class TBaseActiveRelation extends TComponent
+{
+	/**
+	 * @var string name of the related object
+	 */
+	public $name;
+	/**
+	 * @var string name of the related active record class
+	 */
+	public $className;
+	/**
+	 * @var string the foreign key in this relation
+	 */
+	public $foreignKey;
+	/**
+	 * @var mixed list of column names (an array, or a string of names separated by commas) to be selected.
+	 * Do not quote or prefix the column names unless they are used in an expression.
+	 * In that case, you should prefix the column names with '??.'.
+	 */
+	public $select='*';
+	/**
+	 * @var string WHERE clause. For {@link CActiveRelation} descendant classes, column names
+	 * referenced in the condition should be disambiguated with prefix '??.'.
+	 */
+	public $condition='';
+	/**
+	 * @var array the parameters that are to be bound to the condition.
+	 * The keys are parameter placeholder names, and the values are parameter values.
+	 */
+	public $params=array();
+	/**
+	 * @var string GROUP BY clause. For {@link CActiveRelation} descendant classes, column names
+	 * referenced in this property should be disambiguated with prefix '??.'.
+	 */
+	public $group='';
+	/**
+	 * @var string HAVING clause. For {@link CActiveRelation} descendant classes, column names
+	 * referenced in this property should be disambiguated with prefix '??.'.
+	 */
+	public $having='';
+	/**
+	 * @var string ORDER BY clause. For {@link CActiveRelation} descendant classes, column names
+	 * referenced in this property should be disambiguated with prefix '??.'.
+	 */
+	public $order='';
+
+	/**
+	 * Constructor.
+	 * @param string name of the relation
+	 * @param string name of the related active record class
+	 * @param string foreign key for this relation
+	 * @param array additional options (name=>value). The keys must be the property names of this class.
+	 */
+	public function __construct($name,$className,$foreignKey,$options=array())
+	{
+		$this->name=$name;
+		$this->className=$className;
+		$this->foreignKey=$foreignKey;
+		foreach($options as $name=>$value)
+			$this->$name=$value;
+	}
+
+	/**
+	 * Merges this relation with a criteria specified dynamically.
+	 * @param array the dynamically specified criteria
+	 * @since 1.0.5
+	 */
+	public function mergeWith($criteria)
+	{
+		if(isset($criteria['select']) && $this->select!==$criteria['select'])
+		{
+			if($this->select==='*')
+				$this->select=$criteria['select'];
+			else if($criteria['select']!=='*')
+			{
+				$select1=is_string($this->select)?preg_split('/\s*,\s*/',trim($this->select),-1,PREG_SPLIT_NO_EMPTY):$this->select;
+				$select2=is_string($criteria['select'])?preg_split('/\s*,\s*/',trim($criteria['select']),-1,PREG_SPLIT_NO_EMPTY):$criteria['select'];
+				$this->select=array_merge($select1,array_diff($select2,$select1));
+			}
+		}
+
+		if(isset($criteria['condition']) && $this->condition!==$criteria['condition'])
+		{
+			if($this->condition==='')
+				$this->condition=$criteria['condition'];
+			else if($criteria['condition']!=='')
+				$this->condition="({$this->condition}) AND ({$criteria['condition']})";
+		}
+
+		if(isset($criteria['params']) && $this->params!==$criteria['params'])
+			$this->params=array_merge($this->params,$criteria['params']);
+
+		if(isset($criteria['order']) && $this->order!==$criteria['order'])
+		{
+			if($this->order==='')
+				$this->order=$criteria['order'];
+			else if($criteria['order']!=='')
+				$this->order.=', '.$criteria['order'];
+		}
+
+		if(isset($criteria['group']) && $this->group!==$criteria['group'])
+		{
+			if($this->group==='')
+				$this->group=$criteria['group'];
+			else if($criteria['group']!=='')
+				$this->group.=', '.$criteria['group'];
+		}
+
+		if(isset($criteria['having']) && $this->having!==$criteria['having'])
+		{
+			if($this->having==='')
+				$this->having=$criteria['having'];
+			else if($criteria['having']!=='')
+				$this->having="({$this->having}) AND ({$criteria['having']})";
+		}
+	}
+}
+
+
+/**
+ * CStatRelation represents a statistical relational query.
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0.4
+ */
+class TStatRelation extends TBaseActiveRelation
+{
+	/**
+	 * @var string the statistical expression. Defaults to 'COUNT(*)', meaning
+	 * the count of child objects.
+	 */
+	public $select='COUNT(*)';
+	/**
+	 * @var mixed the default value to be assigned to those records that do not
+	 * receive a statistical query result. Defaults to 0.
+	 */
+	public $defaultValue=0;
+
+	/**
+	 * Merges this relation with a criteria specified dynamically.
+	 * @param array the dynamically specified criteria
+	 * @since 1.0.5
+	 */
+	public function mergeWith($criteria)
+	{
+		parent::mergeWith($criteria);
+
+		if(isset($criteria['defaultValue']))
+			$this->defaultValue=$criteria['defaultValue'];
+	}
+}
+
+
+/**
+ * CActiveRelation is the base class for representing active relations that bring back related objects.
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class TActiveRelation extends TBaseActiveRelation
+{
+	/**
+	 * @var string join type. Defaults to 'LEFT OUTER JOIN'.
+	 */
+	public $joinType='LEFT OUTER JOIN';
+	/**
+	 * @var string ON clause. The condition specified here will be appended to the joining condition using AND operator.
+	 * @since 1.0.2
+	 */
+	public $on='';
+	/**
+	 * @var string the alias for the table that this relation refers to. Defaults to null, meaning
+	 * the alias will be the same as the relation name.
+	 * @since 1.0.1
+	 */
+	public $alias;
+	/**
+	 * @var string|array specifies which related objects should be eagerly loaded when this related object is lazily loaded.
+	 * For more details about this property, see {@link CActiveRecord::with()}.
+	 */
+	public $with=array();
+
+	/**
+	 * Merges this relation with a criteria specified dynamically.
+	 * @param array the dynamically specified criteria
+	 * @since 1.0.5
+	 */
+	public function mergeWith($criteria)
+	{
+		if(isset($criteria['condition']) && $this->on!==$criteria['condition'])
+		{
+			if($this->on==='')
+				$this->on=$criteria['condition'];
+			else if($criteria['condition']!=='')
+				$this->on="({$this->on}) AND ({$criteria['condition']})";
+		}
+		unset($criteria['condition']);
+
+		parent::mergeWith($criteria);
+
+		if(isset($criteria['joinType']))
+			$this->joinType=$criteria['joinType'];
+
+		if(isset($criteria['on']) && $this->on!==$criteria['on'])
+		{
+			if($this->on==='')
+				$this->on=$criteria['on'];
+			else if($criteria['on']!=='')
+				$this->on="({$this->on}) AND ({$criteria['on']})";
+		}
+
+		if(isset($criteria['with']))
+			$this->with=$criteria['with'];
+
+		if(isset($criteria['alias']))
+			$this->alias=$criteria['alias'];
+
+		if(isset($criteria['together']))
+			$this->together=$criteria['together'];
+	}
+}
+
+
+/**
+ * CBelongsToRelation represents the parameters specifying a BELONGS_TO relation.
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class TBelongsToRelation extends TActiveRelation
+{
+}
+
+
+/**
+ * CHasOneRelation represents the parameters specifying a HAS_ONE relation.
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class THasOneRelation extends TActiveRelation
+{
+}
+
+
+/**
+ * CHasManyRelation represents the parameters specifying a HAS_MANY relation.
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class THasManyRelation extends TActiveRelation
+{
+	/**
+	 * @var integer limit of the rows to be selected. It is effective only for lazy loading this related object. Defaults to -1, meaning no limit.
+	 */
+	public $limit=-1;
+	/**
+	 * @var integer offset of the rows to be selected. It is effective only for lazy loading this related object. Defaults to -1, meaning no offset.
+	 */
+	public $offset=-1;
+	/**
+	 * @var boolean whether this table should be joined with the primary table.
+	 * When setting this property to be false, the table associated with this relation will
+	 * appear in a separate JOIN statement. Defaults to true, meaning the table will be joined
+	 * together with the primary table. Note that in version 1.0.x, the default value of this property was false.
+	 */
+	public $together=true;
+
+	/**
+	 * Merges this relation with a criteria specified dynamically.
+	 * @param array the dynamically specified criteria
+	 * @since 1.0.5
+	 */
+	public function mergeWith($criteria)
+	{
+		parent::mergeWith($criteria);
+		if(isset($criteria['limit']) && $criteria['limit']>0)
+			$this->limit=$criteria['limit'];
+
+		if(isset($criteria['offset']) && $criteria['offset']>=0)
+			$this->offset=$criteria['offset'];
+	}
+}
+
+
+/**
+ * CManyManyRelation represents the parameters specifying a MANY_MANY relation.
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class TManyManyRelation extends THasManyRelation
+{
+}
+
+
+/**
+ * CActiveRecordMetaData represents the meta-data for an Active Record class.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecord.php 1127 2009-06-13 20:26:35Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0
+ */
+class TActiveRecordMetaData
+{
+	/**
+	 * @var CDbTableSchema the table schema information
+	 */
+	public $tableSchema;
+	/**
+	 * @var array table columns
+	 */
+	public $columns;
+	/**
+	 * @var array list of relations
+	 */
+	public $relations=array();
+	/**
+	 * @var array attribute default values
+	 */
+	public $attributeDefaults=array();
+
+	private $_model;
+
+	/**
+	 * Constructor.
+	 * @param CActiveRecord the model instance
+	 */
+	public function __construct($model)
+	{
+		$this->_model=$model;
+
+		$tableName=$model->tableName();
+		if(($table=$model->getDbConnection()->getSchema()->getTable($tableName))===null)
+			throw new TDbException('The table "'.$tableName.'" for active record class "'.get_class($model).'" cannot be found in the database.');
+			
+		if($table->primaryKey===null)
+			$table->primaryKey=$model->primaryKey();
+		$this->tableSchema=$table;
+		$this->columns=$table->columns;
+
+		foreach($table->columns as $name=>$column)
+		{
+			if(!$column->isPrimaryKey && $column->defaultValue!==null)
+				$this->attributeDefaults[$name]=$column->defaultValue;
+		}
+
+		foreach($model->relations() as $name=>$config)
+		{
+			if(isset($config[0],$config[1],$config[2]))  // relation class, AR class, FK
+				$this->relations[$name]=new $config[0]($name,$config[1],$config[2],array_slice($config,3));
+			else
+				throw new TDbException('Active record "'.get_class($model).'" has an invalid configuration for relation "'.$name.'". It must specify the relation type, the related active record class and the foreign key.');
+		}
+	}
+}
+
+/**
+ * TActiveRecordInvalidFinderResult class.
+ * TActiveRecordInvalidFinderResult defines the enumerable type for possible results
+ * if an invalid {@link TActiveRecord::__call magic-finder} invoked.
+ *
+ * The following enumerable values are defined:
+ * - Null: return null (default)
+ * - Exception: throws a TActiveRecordException
+ *
+ * @author Yves Berkholz <godzilla80@gmx.net>
+ * @version $Id: TActiveRecord.php 2649 2009-05-11 07:44:55Z godzilla80@gmx.net $
+ * @package System.Data.ActiveRecord
+ * @see TActiveRecordManager::setInvalidFinderResult
+ * @see TActiveRecordConfig::setInvalidFinderResult
+ * @see TActiveRecord::setInvalidFinderResult
+ * @since 3.1.5
+ */
+class TActiveRecordInvalidFinderResult extends TEnumerable
+{
+	const Null = 'Null';
+	const Exception = 'Exception';
+}
diff --git a/framework/Db/ActiveRecord/TActiveRecordBehavior.php b/framework/Db/ActiveRecord/TActiveRecordBehavior.php
new file mode 100644
index 00000000..1e4ccbae
--- /dev/null
+++ b/framework/Db/ActiveRecord/TActiveRecordBehavior.php
@@ -0,0 +1,94 @@
+<?php
+/**
+ * CActiveRecordBehavior class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+/**
+ * CActiveRecordBehavior is the base class for behaviors that can be attached to {@link CActiveRecord}.
+ * Compared with {@link CModelBehavior}, CActiveRecordBehavior attaches to more events
+ * that are only defined by {@link CActiveRecord}.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: CActiveRecordBehavior.php 564 2009-01-21 22:07:10Z qiang.xue $
+ * @package System.Db.ActiveRecord
+ * @since 1.0.2
+ */
+class TActiveRecordBehavior extends TModelBehavior
+{
+	/**
+	 * Declares events and the corresponding event handler methods.
+	 * If you override this method, make sure you merge the parent result to the return value.
+	 * @return array events (array keys) and the corresponding event handler methods (array values).
+	 * @see CBehavior::events
+	 */
+	public function events()
+	{
+		return array_merge(parent::events(), array(
+			'onBeforeSave'=>'beforeSave',
+			'onAfterSave'=>'afterSave',
+			'onBeforeDelete'=>'beforeDelete',
+			'onAfterDelete'=>'afterDelete',
+			'onAfterConstruct'=>'afterConstruct',
+			'onAfterFind'=>'afterFind',
+		));
+	}
+
+	/**
+	 * Responds to {@link CActiveRecord::onBeforeSave} event.
+	 * Overrides this method if you want to handle the corresponding event of the {@link CBehavior::owner owner}.
+	 * @param CEvent event parameter
+	 */
+	public function beforeSave($event)
+	{
+	}
+
+	/**
+	 * Responds to {@link CActiveRecord::onAfterSave} event.
+	 * Overrides this method if you want to handle the corresponding event of the {@link CBehavior::owner owner}.
+	 * @param CEvent event parameter
+	 */
+	public function afterSave($event)
+	{
+	}
+
+	/**
+	 * Responds to {@link CActiveRecord::onBeforeDelete} event.
+	 * Overrides this method if you want to handle the corresponding event of the {@link CBehavior::owner owner}.
+	 * @param CEvent event parameter
+	 */
+	public function beforeDelete($event)
+	{
+	}
+
+	/**
+	 * Responds to {@link CActiveRecord::onAfterDelete} event.
+	 * Overrides this method if you want to handle the corresponding event of the {@link CBehavior::owner owner}.
+	 * @param CEvent event parameter
+	 */
+	public function afterDelete($event)
+	{
+	}
+
+	/**
+	 * Responds to {@link CActiveRecord::onAfterConstruct} event.
+	 * Overrides this method if you want to handle the corresponding event of the {@link CBehavior::owner owner}.
+	 * @param CEvent event parameter
+	 */
+	public function afterConstruct($event)
+	{
+	}
+
+	/**
+	 * Responds to {@link CActiveRecord::onAfterFind} event.
+	 * Overrides this method if you want to handle the corresponding event of the {@link CBehavior::owner owner}.
+	 * @param CEvent event parameter
+	 */
+	public function afterFind($event)
+	{
+	}
+}
diff --git a/framework/Db/ActiveRecord/TActiveRecordCriteria.php b/framework/Db/ActiveRecord/TActiveRecordCriteria.php
new file mode 100644
index 00000000..9dded69a
--- /dev/null
+++ b/framework/Db/ActiveRecord/TActiveRecordCriteria.php
@@ -0,0 +1,254 @@
+<?php
+/**
+ * TActiveRecordCriteria class file
+ * Adapts *deprecated* Prado TActiveRecordCriteria to TDbCriteria (Yii)
+ * @class TActiveRecordCriteria
+ * @deprecated
+ * @author Daniel Mueller <tux@penguinfriends.org>
+ */
+
+Prado::using('System.Db.Schema.TDbCriteria');
+
+class TSqlCriteria extends TDbCriteria
+{
+	
+	private $_TDbCriteria = null;
+
+	public function __construct($condition=null, $parameters=array())
+	{
+		if(!is_array($parameters) && func_num_args() > 1)
+			$parameters = array_slice(func_get_args(), 1);
+
+		$this->_TDbCriteria = $this;
+		
+		$this->_TDbCriteria->params = new ArrayObject();
+
+		$param = array(
+			'condition' => ($condition !== null) ? $condition : '',
+			'params' => $parameters
+		);
+	}
+
+	public function getCondition()
+	{
+		return $this->_TDbCriteria->condition;
+	}
+
+	public function setCondition($value)
+	{
+		if(empty($value))
+			return;
+
+		// supporting the following SELECT-syntax:
+		// [ORDER BY {col_name | expr | position}
+		//      [ASC | DESC], ...]
+		//    [LIMIT {[offset,] row_count | row_count OFFSET offset}]
+		// See: http://dev.mysql.com/doc/refman/5.0/en/select.html
+				
+				
+		if(preg_match('/ORDER\s+BY\s+(.*?)(?=LIMIT)|ORDER\s+BY\s+(.*?)$/i', $value, $matches) > 0) {
+			// condition contains ORDER BY
+			$value = str_replace($matches[0], '', $value);
+			if(strlen($matches[1]) > 0) {
+				$this->_TDbCriteria->setOrdersBy($matches[1]);
+			} else if(strlen($matches[2]) > 0) {
+				$this->setOrdersBy($matches[2]);
+			}
+		}
+			
+		if(preg_match('/LIMIT\s+([\d\s,]+)/i', $value, $matches) > 0) {
+				// condition contains limit
+			$value = str_replace($matches[0], '', $value); 
+			// remove limit from query
+			if(strpos($matches[1], ',')) { // both offset and limit given
+				list($offset, $limit) = explode(',', $matches[1]);
+				$this->_TDbCriteria->limit = (int)$limit;
+				$this->_TDbCriteria->offset = (int)$offset;
+			} else { // only limit given
+				$this->_TDbCriteria->limit = (int)$matches[1];
+			}
+		}
+
+		if(preg_match('/OFFSET\s+(\d+)/i', $value, $matches) > 0) {
+			// condition contains offset
+			$value = str_replace($matches[0], '', $value); 
+			// remove offset from query
+			$this->_TDbCriteria->offset = (int)$matches[1]; // set offset in criteria
+		}
+		
+		$this->_TDbCriteria->condition = trim($value);
+	}
+
+	public function getParameters()
+	{
+		return $this->_TDbCriteria->params;
+	}
+
+	public function setParameters($value)
+	{
+		if(is_array($value))
+		{
+			$this->_TDbCriteria->params = $value;
+		}
+		elseif ($value instanceof ArrayAccess)
+		{
+			$this->_TDbCriteria->params = (array)$value;
+		}
+		else
+			throw new TException('Value must be an array or of type ArrayAccess.');
+	}
+
+	public function getIsNamedParameters()
+	{
+		foreach($this->_TDbCriteria->params as $key=>$val)
+			return is_string($key);
+	}
+
+	public function getLimit()
+	{
+		return ($this->_TDbCriteria->limit != -1) ? $this->_TDbCriteria->limit : null;
+	}
+
+	public function setLimit($value)
+	{
+		$this->_TDbCriteria->limit = (int)$value;
+	}
+
+	public function getOffset()
+	{
+		return ($this->_TDbCriteria->offset != -1) ? $this->_TDbCriteria->offset : null;
+	}
+
+	public function setOffset($value)
+	{
+		$this->_TDbCriteria->offset = (int)$value;
+	}
+	
+	public function getOrdersBy()
+	{
+		if(empty($this->_TDbCriteria->order))
+			return array();
+
+		$value=trim(preg_replace('/\s+/',' ', $this->_TDbCriteria->order));
+		$orderBys=array();
+		foreach(explode(',',$value) as $orderBy)
+		{
+			$vs=explode(' ',trim($orderBy));
+			
+		$orderBys[$vs[0]]=isset($vs[1])?$vs[1]:'asc';
+		}
+		return $orderBys;
+	}
+
+	public function setOrdersBy($value)
+	{
+		if(is_string($value))
+			$this->TDbCriteria->order = $value;
+		elseif (is_array($value) || $value instanceof Traversable)
+		{
+			$str = '';
+			foreach($value as $key => $val)
+				$str .= (($str != '') ? ', ': '').$key.' '.$val;
+			
+			$this->_TDbCriteria->order = $str;
+		}
+	}	
+
+	public function __toString()
+	{
+		$str = '';
+		if(strlen((string)$this->getCondition()) > 0)
+			$str .= '"'.(string)$this->getCondition().'"';
+		$params = array();
+		foreach($this->getParameters() as $k=>$v)
+			$params[] = "{$k} => ${v}";
+		if(count($params) > 0)
+			$str .= ', "'.implode(', ',$params).'"';
+		$orders = array();
+		foreach($this->getOrdersBy() as $k=>$v)
+			$orders[] = "{$k} => ${v}";
+		if(count($orders) > 0)
+			$str .= ', "'.implode(', ',$orders).'"';
+		if($this->getLimit() !==null)
+			$str .= ', '.$this->_limit;
+		if($this->getOffset() !== null)
+			$str .= ', '.$this->_offset;
+		return $str;
+	}
+
+	/**
+	 * Returns a property value or an event handler list by property or event name.
+	 * Do not call this method. This is a PHP magic method that we override
+	 * to allow using the following syntax to read a property:
+	 * <code>
+	 * $value=$component->PropertyName;
+	 * </code>
+	 * and to obtain the event handler list for an event,
+	 * <code>
+	 * $eventHandlerList=$component->EventName;
+	 * </code>
+	 * @param string the property name or the event name
+	 * @return mixed the property value or the event handler list
+	 * @throws TInvalidOperationException if the property/event is not defined.
+	 */
+	public function __get($name)
+	{
+		$getter='get'.$name;
+		if(method_exists($this,$getter))
+		{
+			// getting a property
+			return $this->$getter();
+		}
+		else if(strncasecmp($name,'on',2)===0 && method_exists($this,$name))
+		{
+			// getting an event (handler list)
+			$name=strtolower($name);
+			if(!isset($this->_e[$name]))
+				$this->_e[$name]=new TList;
+			return $this->_e[$name];
+		}
+		else
+		{
+			throw new TInvalidOperationException('component_property_undefined',get_class($this),$name);
+		}
+	}
+
+	/**
+	 * Sets value of a component property.
+	 * Do not call this method. This is a PHP magic method that we override
+	 * to allow using the following syntax to set a property or attach an event handler.
+	 * <code>
+	 * $this->PropertyName=$value;
+	 * $this->EventName=$handler;
+	 * </code>
+	 * @param string the property name or event name
+	 * @param mixed the property value or event handler
+	 * @throws TInvalidOperationException If the property is not defined or read-only.
+	 */
+	public function __set($name,$value)
+	{
+		$setter='set'.$name;
+		if(method_exists($this,$setter))
+		{
+			$this->$setter($value);
+		}
+		else if(strncasecmp($name,'on',2)===0 && method_exists($this,$name))
+		{
+			$this->attachEventHandler($name,$value);
+		}
+		else if(method_exists($this,'get'.$name))
+		{
+			throw new TInvalidOperationException('component_property_readonly',get_class($this),$name);
+		}
+		else
+		{
+			throw new TInvalidOperationException('component_property_undefined',get_class($this),$name);
+		}
+	}
+
+}
+
+class TActiveRecordCriteria extends TSqlCriteria
+{
+	
+}
diff --git a/framework/Db/Schema/TDbColumnSchema.php b/framework/Db/Schema/TDbColumnSchema.php
new file mode 100755
index 00000000..f2c4faaa
--- /dev/null
+++ b/framework/Db/Schema/TDbColumnSchema.php
@@ -0,0 +1,145 @@
+<?php
+/**
+ * TDbColumnSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbExpression');
+
+/**
+ * TDbColumnSchema class describes the column meta data of a database table.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TDbColumnSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema
+ * @since 1.0
+ */
+class TDbColumnSchema extends TComponent
+{
+	/**
+	 * @var string name of this column (without quotes).
+	 */
+	public $name;
+	/**
+	 * @var string raw name of this column. This is the quoted name that can be used in SQL queries.
+	 */
+	public $rawName;
+	/**
+	 * @var boolean whether this column can be null.
+	 */
+	public $allowNull;
+	/**
+	 * @var string the DB type of this column.
+	 */
+	public $dbType;
+	/**
+	 * @var string the PHP type of this column.
+	 */
+	public $type;
+	/**
+	 * @var mixed default value of this column
+	 */
+	public $defaultValue;
+	/**
+	 * @var integer size of the column.
+	 */
+	public $size;
+	/**
+	 * @var integer precision of the column data, if it is numeric.
+	 */
+	public $precision;
+	/**
+	 * @var integer scale of the column data, if it is numeric.
+	 */
+	public $scale;
+	/**
+	 * @var boolean whether this column is a primary key
+	 */
+	public $isPrimaryKey;
+	/**
+	 * @var boolean whether this column is a foreign key
+	 */
+	public $isForeignKey;
+
+
+	/**
+	 * Initializes the column with its DB type and default value.
+	 * This sets up the column's PHP type, size, precision, scale as well as default value.
+	 * @param string the column's DB type
+	 * @param mixed the default value
+	 */
+	public function init($dbType, $defaultValue)
+	{
+		$this->dbType=$dbType;
+		$this->extractType($dbType);
+		$this->extractLimit($dbType);
+		if($defaultValue!==null)
+			$this->extractDefault($defaultValue);
+	}
+
+	/**
+	 * Extracts the PHP type from DB type.
+	 * @param string DB type
+	 */
+	protected function extractType($dbType)
+	{
+		if(stripos($dbType,'int')!==false)
+			$this->type='integer';
+		else if(stripos($dbType,'bool')!==false)
+			$this->type='boolean';
+		else if(preg_match('/(real|floa|doub)/i',$dbType))
+			$this->type='double';
+		else
+			$this->type='string';
+	}
+
+	/**
+	 * Extracts size, precision and scale information from column's DB type.
+	 * @param string the column's DB type
+	 */
+	protected function extractLimit($dbType)
+	{
+		if(strpos($dbType,'(') && preg_match('/\((.*)\)/',$dbType,$matches))
+		{
+			$values=explode(',',$matches[1]);
+			$this->size=$this->precision=(int)$values[0];
+			if(isset($values[1]))
+				$this->scale=(int)$values[1];
+		}
+	}
+
+	/**
+	 * Extracts the default value for the column.
+	 * The value is typecasted to correct PHP type.
+	 * @param mixed the default value obtained from metadata
+	 */
+	protected function extractDefault($defaultValue)
+	{
+		$this->defaultValue=$this->typecast($defaultValue);
+	}
+
+	/**
+	 * Converts the input value to the type that this column is of.
+	 * @param mixed input value
+	 * @return mixed converted value
+	 */
+	public function typecast($value)
+	{
+		if(gettype($value)===$this->type || $value===null || $value instanceof TDbExpression)
+			return $value;
+		if($value==='')
+			return $this->type==='string' ? '' : null;
+		switch($this->type)
+		{
+			case 'integer': return (integer)$value;
+			case 'boolean': return (boolean)$value;
+			case 'double': return (double)$value;
+			case 'string': return (string)$value;
+			default: return $value;
+		}
+	}
+}
diff --git a/framework/Db/Schema/TDbCommandBuilder.php b/framework/Db/Schema/TDbCommandBuilder.php
new file mode 100755
index 00000000..7c25888d
--- /dev/null
+++ b/framework/Db/Schema/TDbCommandBuilder.php
@@ -0,0 +1,656 @@
+<?php
+/**
+ * TDbCommandBuilder class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbSchema');
+prado::using('System.Db.Schema.TDbCriteria');
+
+/**
+ * TDbCommandBuilder provides basic methods to create query commands for tables.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TDbCommandBuilder.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema
+ * @since 1.0
+ */
+class TDbCommandBuilder extends TComponent
+{
+	const PARAM_PREFIX=':yp';
+
+	private $_schema;
+	private $_connection;
+
+	/**
+	 * @param TDbSchema the schema for this command builder
+	 */
+	public function __construct($schema)
+	{
+		$this->_schema=$schema;
+		$this->_connection=$schema->getDbConnection();
+	}
+
+	/**
+	 * @return TDbConnection database connection.
+	 */
+	public function getDbConnection()
+	{
+		return $this->_connection;
+	}
+
+	/**
+	 * @return TDbSchema the schema for this command builder.
+	 */
+	public function getSchema()
+	{
+		return $this->_schema;
+	}
+
+	/**
+	 * Returns the last insertion ID for the specified table.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @return mixed last insertion id. Null is returned if no sequence name.
+	 */
+	public function getLastInsertID($table)
+	{
+		$this->ensureTable($table);
+		if($table->sequenceName!==null)
+			return $this->_connection->getLastInsertID($table->sequenceName);
+		else
+			return null;
+	}
+
+	/**
+	 * Creates a SELECT command for a single table.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param TDbCriteria the query criteria
+	 * @return TDbCommand query command.
+	 */
+	public function createFindCommand($table,$criteria)
+	{
+		$this->ensureTable($table);
+		$select=is_array($criteria->select) ? implode(', ',$criteria->select) : $criteria->select;
+		$sql="SELECT {$select} FROM {$table->rawName}";
+		$sql=$this->applyJoin($sql,$criteria->join);
+		$sql=$this->applyCondition($sql,$criteria->condition);
+		$sql=$this->applyGroup($sql,$criteria->group);
+		$sql=$this->applyHaving($sql,$criteria->having);
+		$sql=$this->applyOrder($sql,$criteria->order);
+		$sql=$this->applyLimit($sql,$criteria->limit,$criteria->offset);
+		$command=$this->_connection->createCommand($sql);
+		$this->bindValues($command,$criteria->params);
+		return $command;
+	}
+
+	/**
+	 * Creates a COUNT(*) command for a single table.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param TDbCriteria the query criteria
+	 * @return TDbCommand query command.
+	 */
+	public function createCountCommand($table,$criteria)
+	{
+		$this->ensureTable($table);
+		$criteria->select='COUNT(*)';
+		return $this->createFindCommand($table,$criteria);
+	}
+
+	/**
+	 * Creates a DELETE command.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param TDbCriteria the query criteria
+	 * @return TDbCommand delete command.
+	 */
+	public function createDeleteCommand($table,$criteria)
+	{
+		$this->ensureTable($table);
+		$sql="DELETE FROM {$table->rawName}";
+		$sql=$this->applyJoin($sql,$criteria->join);
+		$sql=$this->applyCondition($sql,$criteria->condition);
+		$sql=$this->applyGroup($sql,$criteria->group);
+		$sql=$this->applyHaving($sql,$criteria->having);
+		$sql=$this->applyOrder($sql,$criteria->order);
+		$sql=$this->applyLimit($sql,$criteria->limit,$criteria->offset);
+		$command=$this->_connection->createCommand($sql);
+		$this->bindValues($command,$criteria->params);
+		return $command;
+	}
+
+	/**
+	 * Creates an INSERT command.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param array data to be inserted (column name=>column value). If a key is not a valid column name, the corresponding value will be ignored.
+	 * @return TDbCommand insert command
+	 */
+	public function createInsertCommand($table,$data)
+	{
+		$this->ensureTable($table);
+		$fields=array();
+		$values=array();
+		$placeholders=array();
+		$i=0;
+		foreach($data as $name=>$value)
+		{
+			if(($column=$table->getColumn($name))!==null && ($value!==null || $column->allowNull))
+			{
+				$fields[]=$column->rawName;
+				if($value instanceof TDbExpression)
+					$placeholders[]=(string)$value;
+				else
+				{
+					$placeholders[]=self::PARAM_PREFIX.$i;
+					$values[self::PARAM_PREFIX.$i]=$column->typecast($value);
+					$i++;
+				}
+			}
+		}
+		$sql="INSERT INTO {$table->rawName} (".implode(', ',$fields).') VALUES ('.implode(', ',$placeholders).')';
+		$command=$this->_connection->createCommand($sql);
+
+		foreach($values as $name=>$value)
+			$command->bindValue($name,$value);
+
+		return $command;
+	}
+
+	/**
+	 * Creates an UPDATE command.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param array list of columns to be updated (name=>value)
+	 * @param TDbCriteria the query criteria
+	 * @return TDbCommand update command.
+	 */
+	public function createUpdateCommand($table,$data,$criteria)
+	{
+		$this->ensureTable($table);
+		$fields=array();
+		$values=array();
+		$bindByPosition=isset($criteria->params[0]);
+		$i=0;
+		foreach($data as $name=>$value)
+		{
+			if(($column=$table->getColumn($name))!==null)
+			{
+				if($value instanceof TDbExpression)
+					$fields[]=$column->rawName.'='.(string)$value;
+				else if($bindByPosition)
+				{
+					$fields[]=$column->rawName.'=?';
+					$values[]=$column->typecast($value);
+				}
+				else
+				{
+					$fields[]=$column->rawName.'='.self::PARAM_PREFIX.$i;
+					$values[self::PARAM_PREFIX.$i]=$column->typecast($value);
+					$i++;
+				}
+			}
+		}
+		if($fields===array())
+			throw new TDbException('No columns are being updated for table "{0}".',
+				$table->name);
+		$sql="UPDATE {$table->rawName} SET ".implode(', ',$fields);
+		$sql=$this->applyJoin($sql,$criteria->join);
+		$sql=$this->applyCondition($sql,$criteria->condition);
+		$sql=$this->applyOrder($sql,$criteria->order);
+		$sql=$this->applyLimit($sql,$criteria->limit,$criteria->offset);
+
+		$command=$this->_connection->createCommand($sql);
+		$this->bindValues($command,array_merge($values,$criteria->params));
+
+		return $command;
+	}
+
+	/**
+	 * Creates an UPDATE command that increments/decrements certain columns.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param TDbCriteria the query criteria
+	 * @param array counters to be updated (counter increments/decrements indexed by column names.)
+	 * @return TDbCommand the created command
+	 * @throws CException if no counter is specified
+	 */
+	public function createUpdateCounterCommand($table,$counters,$criteria)
+	{
+		$this->ensureTable($table);
+		$fields=array();
+		foreach($counters as $name=>$value)
+		{
+			if(($column=$table->getColumn($name))!==null)
+			{
+				$value=(int)$value;
+				if($value<0)
+					$fields[]="{$column->rawName}={$column->rawName}-".(-$value);
+				else
+					$fields[]="{$column->rawName}={$column->rawName}+".$value;
+			}
+		}
+		if($fields!==array())
+		{
+			$sql="UPDATE {$table->rawName} SET ".implode(', ',$fields);
+			$sql=$this->applyJoin($sql,$criteria->join);
+			$sql=$this->applyCondition($sql,$criteria->condition);
+			$sql=$this->applyOrder($sql,$criteria->order);
+			$sql=$this->applyLimit($sql,$criteria->limit,$criteria->offset);
+			$command=$this->_connection->createCommand($sql);
+			$this->bindValues($command,$criteria->params);
+			return $command;
+		}
+		else
+			throw new TDbException('No counter columns are being updated for table "{0}".',
+				$table->name);
+	}
+
+	/**
+	 * Creates a command based on a given SQL statement.
+	 * @param string the explicitly specified SQL statement
+	 * @param array parameters that will be bound to the SQL statement
+	 * @return TDbCommand the created command
+	 */
+	public function createSqlCommand($sql,$params=array())
+	{
+		$command=$this->_connection->createCommand($sql);
+		$this->bindValues($command,$params);
+		return $command;
+	}
+
+	/**
+	 * Alters the SQL to apply JOIN clause.
+	 * @param string the SQL statement to be altered
+	 * @param string the JOIN clause (starting with join type, such as INNER JOIN)
+	 * @return string the altered SQL statement
+	 */
+	public function applyJoin($sql,$join)
+	{
+		if($join!=='')
+			return $sql.' '.$join;
+		else
+			return $sql;
+	}
+
+	/**
+	 * Alters the SQL to apply WHERE clause.
+	 * @param string the SQL statement without WHERE clause
+	 * @param string the WHERE clause (without WHERE keyword)
+	 * @return string the altered SQL statement
+	 */
+	public function applyCondition($sql,$condition)
+	{
+		if($condition!=='')
+			return $sql.' WHERE '.$condition;
+		else
+			return $sql;
+	}
+
+	/**
+	 * Alters the SQL to apply ORDER BY.
+	 * @param string SQL statement without ORDER BY.
+	 * @param string column ordering
+	 * @return string modified SQL applied with ORDER BY.
+	 */
+	public function applyOrder($sql,$orderBy)
+	{
+		if($orderBy!=='')
+			return $sql.' ORDER BY '.$orderBy;
+		else
+			return $sql;
+	}
+
+	/**
+	 * Alters the SQL to apply LIMIT and OFFSET.
+	 * Default implementation is applicable for PostgreSQL, MySQL and SQLite.
+	 * @param string SQL query string without LIMIT and OFFSET.
+	 * @param integer maximum number of rows, -1 to ignore limit.
+	 * @param integer row offset, -1 to ignore offset.
+	 * @return string SQL with LIMIT and OFFSET
+	 */
+	public function applyLimit($sql,$limit,$offset)
+	{
+		if($limit>=0)
+			$sql.=' LIMIT '.(int)$limit;
+		if($offset>0)
+			$sql.=' OFFSET '.(int)$offset;
+		return $sql;
+	}
+
+	/**
+	 * Alters the SQL to apply GROUP BY.
+	 * @param string SQL query string without GROUP BY.
+	 * @param string GROUP BY
+	 * @return string SQL with GROUP BY.
+	 */
+	public function applyGroup($sql,$group)
+	{
+		if($group!=='')
+			return $sql.' GROUP BY '.$group;
+		else
+			return $sql;
+	}
+
+	/**
+	 * Alters the SQL to apply HAVING.
+	 * @param string SQL query string without HAVING
+	 * @param string HAVING
+	 * @return string SQL with HAVING
+	 * @since 1.0.1
+	 */
+	public function applyHaving($sql,$having)
+	{
+		if($having!=='')
+			return $sql.' HAVING '.$having;
+		else
+			return $sql;
+	}
+
+	/**
+	 * Binds parameter values for an SQL command.
+	 * @param TDbCommand database command
+	 * @param array values for binding (integer-indexed array for question mark placeholders, string-indexed array for named placeholders)
+	 */
+	public function bindValues($command, $values)
+	{
+		if(($n=count($values))===0)
+			return;
+		if(isset($values[0])) // question mark placeholders
+		{
+			for($i=0;$i<$n;++$i)
+				$command->bindValue($i+1,$values[$i]);
+		}
+		else // named placeholders
+		{
+			foreach($values as $name=>$value)
+			{
+				if($name[0]!==':')
+					$name=':'.$name;
+				$command->bindValue($name,$value);
+			}
+		}
+	}
+
+	/**
+	 * Creates a query criteria.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param mixed query condition or criteria.
+	 * If a string, it is treated as query condition (the WHERE clause);
+	 * If an array, it is treated as the initial values for constructing a {@link TDbCriteria} object;
+	 * Otherwise, it should be an instance of {@link TDbCriteria}.
+	 * @param array parameters to be bound to an SQL statement.
+	 * This is only used when the first parameter is a string (query condition).
+	 * In other cases, please use {@link TDbCriteria::params} to set parameters.
+	 * @return TDbCriteria the created query criteria
+	 * @throws CException if the condition is not string, array and TDbCriteria
+	 */
+	public function createCriteria($condition='',$params=array())
+	{
+		if(is_array($condition))
+			$criteria=new TDbCriteria($condition);
+		else if($condition instanceof TDbCriteria)
+			$criteria=clone $condition;
+		else
+		{
+			$criteria=new TDbCriteria;
+			$criteria->condition=$condition;
+			$criteria->params=$params;
+		}
+		return $criteria;
+	}
+
+	/**
+	 * Creates a query criteria with the specified primary key.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param mixed primary key value(s). Use array for multiple primary keys. For composite key, each key value must be an array (column name=>column value).
+	 * @param mixed query condition or criteria.
+	 * If a string, it is treated as query condition;
+	 * If an array, it is treated as the initial values for constructing a {@link TDbCriteria};
+	 * Otherwise, it should be an instance of {@link TDbCriteria}.
+	 * @param array parameters to be bound to an SQL statement.
+	 * This is only used when the second parameter is a string (query condition).
+	 * In other cases, please use {@link TDbCriteria::params} to set parameters.
+	 * @return TDbCriteria the created query criteria
+	 */
+	public function createPkCriteria($table,$pk,$condition='',$params=array())
+	{
+		$this->ensureTable($table);
+		$criteria=$this->createCriteria($condition,$params);
+		if(!is_array($pk)) // single key
+			$pk=array($pk);
+		if(is_array($table->primaryKey) && !isset($pk[0]) && $pk!==array()) // single composite key
+			$pk=array($pk);
+		$condition=$this->createInCondition($table,$table->primaryKey,$pk);
+		if($criteria->condition!=='')
+			$criteria->condition=$condition.' AND ('.$criteria->condition.')';
+		else
+			$criteria->condition=$condition;
+
+		return $criteria;
+	}
+
+	/**
+	 * Generates the expression for selecting rows of specified primary key values.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param array list of primary key values to be selected within
+	 * @param string column prefix (ended with dot). If null, it will be the table name
+	 * @return string the expression for selection
+	 */
+	public function createPkCondition($table,$values,$prefix=null)
+	{
+		$this->ensureTable($table);
+		return $this->createInCondition($table,$table->primaryKey,$values,$prefix);
+	}
+
+	/**
+	 * Creates a query criteria with the specified column values.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param array column values that should be matched in the query (name=>value)
+	 * @param mixed query condition or criteria.
+	 * If a string, it is treated as query condition;
+	 * If an array, it is treated as the initial values for constructing a {@link TDbCriteria};
+	 * Otherwise, it should be an instance of {@link TDbCriteria}.
+	 * @param array parameters to be bound to an SQL statement.
+	 * This is only used when the second parameter is a string (query condition).
+	 * In other cases, please use {@link TDbCriteria::params} to set parameters.
+	 * @return TDbCriteria the created query criteria
+	 */
+	public function createColumnCriteria($table,$columns,$condition='',$params=array())
+	{
+		$this->ensureTable($table);
+		$criteria=$this->createCriteria($condition,$params);
+		$bindByPosition=isset($criteria->params[0]);
+		$conditions=array();
+		$values=array();
+		$i=0;
+		foreach($columns as $name=>$value)
+		{
+			if(($column=$table->getColumn($name))!==null)
+			{
+				if($value!==null)
+				{
+					if($bindByPosition)
+					{
+						$conditions[]=$table->rawName.'.'.$column->rawName.'=?';
+						$values[]=$value;
+					}
+					else
+					{
+						$conditions[]=$table->rawName.'.'.$column->rawName.'='.self::PARAM_PREFIX.$i;
+						$values[self::PARAM_PREFIX.$i]=$value;
+						$i++;
+					}
+				}
+				else
+					$conditions[]=$table->rawName.'.'.$column->rawName.' IS NULL';
+			}
+			else
+				throw new TDbException('Table "{0}" does not have a column named "{1}".',
+					$table->name,$name);
+		}
+		$criteria->params=array_merge($values,$criteria->params);
+		if(isset($conditions[0]))
+		{
+			if($criteria->condition!=='')
+				$criteria->condition=implode(' AND ',$conditions).' AND ('.$criteria->condition.')';
+			else
+				$criteria->condition=implode(' AND ',$conditions);
+		}
+		return $criteria;
+	}
+
+	/**
+	 * Generates the expression for searching the specified keywords within a list of columns.
+	 * The search expression is generated using the 'LIKE' SQL syntax.
+	 * Every word in the keywords must be present and appear in at least one of the columns.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param array list of column names for potential search condition.
+	 * @param mixed search keywords. This can be either a string with space-separated keywords or an array of keywords.
+	 * @param string optional column prefix (with dot at the end). If null, the table name will be used as the prefix.
+	 * @param boolean whether the search is case-sensitive. Defaults to true. This parameter
+	 * has been available since version 1.0.4.
+	 * @return string SQL search condition matching on a set of columns. An empty string is returned
+	 * if either the column array or the keywords are empty.
+	 */
+	public function createSearchCondition($table,$columns,$keywords,$prefix=null,$caseSensitive=true)
+	{
+		$this->ensureTable($table);
+		if(!is_array($keywords))
+			$keywords=preg_split('/\s+/u',$keywords,-1,PREG_SPLIT_NO_EMPTY);
+		if(empty($keywords))
+			return '';
+		if($prefix===null)
+			$prefix=$table->rawName.'.';
+		$conditions=array();
+		foreach($columns as $name)
+		{
+			if(($column=$table->getColumn($name))===null)
+				throw new TDbException('Table "{0}" does not have a column named "{0}".',
+					$table->name,$name);
+			$condition=array();
+			foreach($keywords as $keyword)
+			{
+				if($caseSensitive)
+					$condition[]=$prefix.$column->rawName.' LIKE '.$this->_connection->quoteValue('%'.$keyword.'%');
+				else
+					$condition[]='LOWER('.$prefix.$column->rawName.') LIKE LOWER('.$this->_connection->quoteValue('%'.$keyword.'%').')';
+			}
+			$conditions[]=implode(' AND ',$condition);
+		}
+		return '('.implode(' OR ',$conditions).')';
+	}
+
+	/**
+	 * Generates the expression for selecting rows of specified primary key values.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param mixed the column name(s). It can be either a string indicating a single column
+	 * or an array of column names. If the latter, it stands for a composite key.
+	 * @param array list of key values to be selected within
+	 * @param string column prefix (ended with dot). If null, it will be the table name
+	 * @return string the expression for selection
+	 * @since 1.0.4
+	 */
+	public function createInCondition($table,$columnName,$values,$prefix=null)
+	{
+		if(($n=count($values))<1)
+			return '0=1';
+
+		$this->ensureTable($table);
+
+		if($prefix===null)
+			$prefix=$table->rawName.'.';
+
+		$db=$this->_connection;
+
+		if(is_array($columnName) && count($columnName)===1)
+			$columnName=reset($columnName);
+
+		if(is_string($columnName)) // simple key
+		{
+			if(!isset($table->columns[$columnName]))
+				throw new TDbException('Table "{0}" does not have a column named "{1}".',
+				$table->name, $columnName);
+			$column=$table->columns[$columnName];
+
+			foreach($values as &$value)
+			{
+				$value=$column->typecast($value);
+				if(is_string($value))
+					$value=$db->quoteValue($value);
+			}
+			if($n===1)
+				return $prefix.$column->rawName.($values[0]===null?' IS NULL':'='.$values[0]);
+			else
+				return $prefix.$column->rawName.' IN ('.implode(', ',$values).')';
+		}
+		else if(is_array($columnName)) // composite key: $values=array(array('pk1'=>'v1','pk2'=>'v2'),array(...))
+		{
+			foreach($columnName as $name)
+			{
+				if(!isset($table->columns[$name]))
+					throw new TDbException('Table "{0}" does not have a column named "{1}".',
+					$table->name, $name);
+
+				for($i=0;$i<$n;++$i)
+				{
+					if(isset($values[$i][$name]))
+					{
+						$value=$table->columns[$name]->typecast($values[$i][$name]);
+						if(is_string($value))
+							$values[$i][$name]=$db->quoteValue($value);
+						else
+							$values[$i][$name]=$value;
+					}
+					else
+						throw new TDbException('The value for the column "{1}" is not supplied when querying the table "{0}".',
+							$table->name,$name);
+				}
+			}
+			if(count($values)===1)
+			{
+				$entries=array();
+				foreach($values[0] as $name=>$value)
+					$entries[]=$prefix.$table->columns[$name]->rawName.($value===null?' IS NULL':'='.$value);
+				return implode(' AND ',$entries);
+			}
+
+			return $this->createCompositeInCondition($table,$values,$prefix);
+		}
+		else
+			throw new TDbException('Column name must be either a string or an array.');
+	}
+
+	/**
+	 * Generates the expression for selecting rows with specified composite key values.
+	 * @param TDbTableSchema the table schema
+	 * @param array list of primary key values to be selected within
+	 * @param string column prefix (ended with dot)
+	 * @return string the expression for selection
+	 * @since 1.0.4
+	 */
+	protected function createCompositeInCondition($table,$values,$prefix)
+	{
+		$keyNames=array();
+		foreach(array_keys($values[0]) as $name)
+			$keyNames[]=$prefix.$table->columns[$name]->rawName;
+		$vs=array();
+		foreach($values as $value)
+			$vs[]='('.implode(', ',$value).')';
+		return '('.implode(', ',$keyNames).') IN ('.implode(', ',$vs).')';
+	}
+
+	/**
+	 * Checks if the parameter is a valid table schema.
+	 * If it is a string, the corresponding table schema will be retrieved.
+	 * @param mixed table schema ({@link TDbTableSchema}) or table name (string).
+	 * If this refers to a valid table name, this parameter will be returned with the corresponding table schema.
+	 * @throws TDbException if the table name is not valid
+	 * @since 1.0.4
+	 */
+	protected function ensureTable(&$table)
+	{
+		if(is_string($table) && ($table=$this->_schema->getTable($tableName=$table))===null)
+			throw new TDbException('Table "{0}" does not exist.',
+				$tableName);
+	}
+}
diff --git a/framework/Db/Schema/TDbCriteria.php b/framework/Db/Schema/TDbCriteria.php
new file mode 100755
index 00000000..3dab036a
--- /dev/null
+++ b/framework/Db/Schema/TDbCriteria.php
@@ -0,0 +1,166 @@
+<?php
+/**
+ * TDbCriteria class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+/**
+ * TDbCriteria represents a query criteria, such as conditions, ordering by, limit/offset.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TDbCriteria.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package system.db.schema
+ * @since 1.0
+ */
+class TDbCriteria
+{
+	/**
+	 * @var mixed the columns being selected. This refers to the SELECT clause in an SQL
+	 * statement. The property can be either a string (column names separated by commas)
+	 * or an array of column names. Defaults to '*', meaning all columns.
+	 */
+	public $select='*';
+	/**
+	 * @var string query condition. This refers to the WHERE clause in an SQL statement.
+	 * For example, <code>age>31 AND team=1</code>.
+	 */
+	public $condition='';
+	/**
+	 * @var array list of query parameter values indexed by parameter placeholders.
+	 * For example, <code>array(':name'=>'Dan', ':age'=>31)</code>.
+	 */
+	public $params=array();
+	/**
+	 * @var integer maximum number of records to be returned. If less than 0, it means no limit.
+	 */
+	public $limit=-1;
+	/**
+	 * @var integer zero-based offset from where the records are to be returned. If less than 0, it means starting from the beginning.
+	 */
+	public $offset=-1;
+	/**
+	 * @var string how to sort the query results. This refers to the ORDER BY clause in an SQL statement.
+	 */
+	public $order='';
+	/**
+	 * @var string how to group the query results. This refers to the GROUP BY clause in an SQL statement.
+	 * For example, <code>'projectID, teamID'</code>.
+	 */
+	public $group='';
+	/**
+	 * @var string how to join with other tables. This refers to the JOIN clause in an SQL statement.
+	 * For example, <code>'LEFT JOIN users ON users.id=authorID'</code>.
+	 */
+	public $join='';
+	/**
+	 * @var string the condition to be applied with GROUP-BY clause.
+	 * For example, <code>'SUM(revenue)<50000'</code>.
+	 * @since 1.0.1
+	 */
+	public $having='';
+
+	/**
+	 * Constructor.
+	 * @param array criteria initial property values (indexed by property name)
+	 */
+	public function __construct($data=array())
+	{
+		foreach($data as $name=>$value)
+			$this->$name=$value;
+	}
+
+	/**
+	 * Merges with another criteria.
+	 * In general, the merging makes the resulting criteria more restrictive.
+	 * For example, if both criterias have conditions, they will be 'AND' together.
+	 * Also, the criteria passed as the parameter takes precedence in case
+	 * two options cannot be merged (e.g. LIMIT, OFFSET).
+	 * @param TDbCriteria the criteria to be merged with.
+	 * @param boolean whether to use 'AND' to merge condition and having options.
+	 * If false, 'OR' will be used instead. Defaults to 'AND'. This parameter has been
+	 * available since version 1.0.6.
+	 * @since 1.0.5
+	 */
+	public function mergeWith($criteria,$useAnd=true)
+	{
+		$and=$useAnd ? 'AND' : 'OR';
+		if(is_array($criteria))
+			$criteria=new self($criteria);
+		if($this->select!==$criteria->select)
+		{
+			if($this->select==='*')
+				$this->select=$criteria->select;
+			else if($criteria->select!=='*')
+			{
+				$select1=is_string($this->select)?preg_split('/\s*,\s*/',trim($this->select),-1,PREG_SPLIT_NO_EMPTY):$this->select;
+				$select2=is_string($criteria->select)?preg_split('/\s*,\s*/',trim($criteria->select),-1,PREG_SPLIT_NO_EMPTY):$criteria->select;
+				$this->select=array_merge($select1,array_diff($select2,$select1));
+			}
+		}
+
+		if($this->condition!==$criteria->condition)
+		{
+			if($this->condition==='')
+				$this->condition=$criteria->condition;
+			else if($criteria->condition!=='')
+				$this->condition="({$this->condition}) $and ({$criteria->condition})";
+		}
+
+		if($this->params!==$criteria->params)
+			$this->params=array_merge($this->params,$criteria->params);
+
+		if($criteria->limit>0)
+			$this->limit=$criteria->limit;
+
+		if($criteria->offset>=0)
+			$this->offset=$criteria->offset;
+
+		if($this->order!==$criteria->order)
+		{
+			if($this->order==='')
+				$this->order=$criteria->order;
+			else if($criteria->order!=='')
+				$this->order.=', '.$criteria->order;
+		}
+
+		if($this->group!==$criteria->group)
+		{
+			if($this->group==='')
+				$this->group=$criteria->group;
+			else if($criteria->group!=='')
+				$this->group.=', '.$criteria->group;
+		}
+
+		if($this->join!==$criteria->join)
+		{
+			if($this->join==='')
+				$this->join=$criteria->join;
+			else if($criteria->join!=='')
+				$this->join.=' '.$criteria->join;
+		}
+
+		if($this->having!==$criteria->having)
+		{
+			if($this->having==='')
+				$this->having=$criteria->having;
+			else if($criteria->having!=='')
+				$this->having="({$this->having}) $and ({$criteria->having})";
+		}
+	}
+
+	/**
+	 * @return array the array representation of the criteria
+	 * @since 1.0.6
+	 */
+	public function toArray()
+	{
+		$result=array();
+		foreach(array('select', 'condition', 'params', 'limit', 'offset', 'order', 'group', 'join', 'having') as $name)
+			$result[$name]=$this->$name;
+		return $result;
+	}
+}
diff --git a/framework/Db/Schema/TDbExpression.php b/framework/Db/Schema/TDbExpression.php
new file mode 100755
index 00000000..86b9a1ef
--- /dev/null
+++ b/framework/Db/Schema/TDbExpression.php
@@ -0,0 +1,49 @@
+<?php
+/**
+ * TDbExpression class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+/**
+ * TDbExpression represents a DB expression that does not need escaping.
+ * TDbExpression is mainly used in {@link CActiveRecord} as attribute values.
+ * When inserting or updating a {@link CActiveRecord}, attribute values of
+ * type TDbExpression will be directly put into the corresponding SQL statement
+ * without escaping. A typical usage is that an attribute is set with 'NOW()'
+ * expression so that saving the record would fill the corresponding column
+ * with the current DB server timestamp.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TDbExpression.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package system.db.schema
+ * @since 1.0.2
+ */
+class TDbExpression extends TComponent
+{
+	/**
+	 * @var string the DB expression
+	 */
+	public $expression;
+
+	/**
+	 * Constructor.
+	 * @param string the DB expression
+	 */
+	public function __construct($expression)
+	{
+		$this->expression=$expression;
+	}
+
+	/**
+	 * String magic method
+	 * @return string the DB expression
+	 */
+	public function __toString()
+	{
+		return $this->expression;
+	}
+}
\ No newline at end of file
diff --git a/framework/Db/Schema/TDbSchema.php b/framework/Db/Schema/TDbSchema.php
new file mode 100755
index 00000000..6837b7e5
--- /dev/null
+++ b/framework/Db/Schema/TDbSchema.php
@@ -0,0 +1,193 @@
+<?php
+/**
+ * TDbSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbCommandBuilder');
+
+/**
+ * TDbSchema is the base class for retrieving metadata information.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TDbSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema
+ * @since 1.0
+ */
+abstract class TDbSchema extends TComponent
+{
+	private $_tableNames=array();
+	private $_tables=array();
+	private $_connection;
+	private $_builder;
+	private $_cacheExclude=array();
+
+	/**
+	 * Creates a table instance representing the metadata for the named table.
+	 * @return TDbTableSchema driver dependent table metadata, null if the table does not exist.
+	 */
+	abstract protected function createTable($name);
+
+	/**
+	 * Constructor.
+	 * @param TDbConnection database connection.
+	 */
+	public function __construct($conn)
+	{
+		$conn->setActive(true);
+		$this->_connection=$conn;
+		foreach($conn->schemaCachingExclude as $name)
+			$this->_cacheExclude[$name]=true;
+	}
+
+	/**
+	 * @return TDbConnection database connection. The connection is active.
+	 */
+	public function getDbConnection()
+	{
+		return $this->_connection;
+	}
+
+	/**
+	 * Obtains the metadata for the named table.
+	 * @param string table name
+	 * @return TDbTableSchema table metadata. Null if the named table does not exist.
+	 */
+	public function getTable($name)
+	{
+		if(isset($this->_tables[$name]))
+			return $this->_tables[$name];
+		else if(!isset($this->_cacheExclude[$name]) && ($duration=$this->_connection->schemaCachingDuration)>0 && ($cache=prado::getApplication()->getCache())!==null)
+		{
+			$key='prado:dbschema'.$this->_connection->connectionString.':'.$this->_connection->username.':'.$name;
+			if(($table=$cache->get($key))===false)
+			{
+				$table=$this->createTable($name);
+				$cache->set($key,$table,$duration);
+			}
+			return $this->_tables[$name]=$table;
+		}
+		else
+			return $this->_tables[$name]=$this->createTable($name);
+	}
+
+	/**
+	 * Returns the metadata for all tables in the database.
+	 * @param string the schema of the tables. Defaults to empty string, meaning the current or default schema.
+	 * @return array the metadata for all tables in the database.
+	 * Each array element is an instance of {@link TDbTableSchema} (or its child class).
+	 * The array keys are table names.
+	 * @since 1.0.2
+	 */
+	public function getTables($schema='')
+	{
+		$tables=array();
+		foreach($this->getTableNames($schema) as $name)
+			$tables[$name]=$this->getTable($name);
+		return $tables;
+	}
+
+	/**
+	 * Returns all table names in the database.
+	 * @param string the schema of the tables. Defaults to empty string, meaning the current or default schema.
+	 * If not empty, the returned table names will be prefixed with the schema name.
+	 * @return array all table names in the database.
+	 * @since 1.0.2
+	 */
+	public function getTableNames($schema='')
+	{
+		if(!isset($this->_tableNames[$schema]))
+			$this->_tableNames[$schema]=$this->findTableNames($schema);
+		return $this->_tableNames[$schema];
+	}
+
+	/**
+	 * @return TDbCommandBuilder the SQL command builder for this connection.
+	 */
+	public function getCommandBuilder()
+	{
+		if($this->_builder!==null)
+			return $this->_builder;
+		else
+			return $this->_builder=$this->createCommandBuilder();
+	}
+
+	/**
+	 * Refreshes the schema.
+	 * This method resets the loaded table metadata and command builder
+	 * so that they can be recreated to reflect the change of schema.
+	 */
+	public function refresh()
+	{
+		$this->_tables=array();
+		$this->_builder=null;
+	}
+
+	/**
+	 * Quotes a table name for use in a query.
+	 * @param string table name
+	 * @return string the properly quoted table name
+	 */
+	public function quoteTableName($name)
+	{
+		return "'".$name."'";
+	}
+
+	/**
+	 * Quotes a column name for use in a query.
+	 * @param string column name
+	 * @return string the properly quoted column name
+	 */
+	public function quoteColumnName($name)
+	{
+		return '"'.$name.'"';
+	}
+
+	/**
+	 * Compares two table names.
+	 * The table names can be either quoted or unquoted. This method
+	 * will consider both cases.
+	 * @param string table name 1
+	 * @param string table name 2
+	 * @return boolean whether the two table names refer to the same table.
+	 */
+	public function compareTableNames($name1,$name2)
+	{
+		$name1=str_replace(array('"','`',"'"),'',$name1);
+		$name2=str_replace(array('"','`',"'"),'',$name2);
+		if(($pos=strrpos($name1,'.'))!==false)
+			$name1=substr($name1,$pos+1);
+		if(($pos=strrpos($name2,'.'))!==false)
+			$name2=substr($name2,$pos+1);
+		return $name1===$name2;
+	}
+
+	/**
+	 * Creates a command builder for the database.
+	 * This method may be overridden by child classes to create a DBMS-specific command builder.
+	 * @return TDbCommandBuilder command builder instance
+	 */
+	protected function createCommandBuilder()
+	{
+		return new TDbCommandBuilder($this);
+	}
+
+	/**
+	 * Returns all table names in the database.
+	 * This method should be overridden by child classes in order to support this feature
+	 * because the default implemenation simply throws an exception.
+	 * @param string the schema of the tables. Defaults to empty string, meaning the current or default schema.
+	 * If not empty, the returned table names will be prefixed with the schema name.
+	 * @return array all table names in the database.
+	 * @since 1.0.2
+	 */
+	protected function findTableNames($schema='')
+	{
+		throw new TDbException('{0} does not support fetching all table names.',
+			get_class($this));
+	}
+}
diff --git a/framework/Db/Schema/TDbTableSchema.php b/framework/Db/Schema/TDbTableSchema.php
new file mode 100755
index 00000000..eaeda1b4
--- /dev/null
+++ b/framework/Db/Schema/TDbTableSchema.php
@@ -0,0 +1,76 @@
+<?php
+/**
+ * TDbTableSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+/**
+ * TDbTableSchema is the base class for representing the metadata of a database table.
+ *
+ * It may be extended by different DBMS driver to provide DBMS-specific table metadata.
+ *
+ * TDbTableSchema provides the following information about a table:
+ * <ul>
+ * <li>{@link name}</li>
+ * <li>{@link rawName}</li>
+ * <li>{@link columns}</li>
+ * <li>{@link primaryKey}</li>
+ * <li>{@link foreignKeys}</li>
+ * <li>{@link sequenceName}</li>
+ * </ul>
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TDbTableSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package system.db.schema
+ * @since 1.0
+ */
+class TDbTableSchema extends TComponent
+{
+	/**
+	 * @var string name of this table.
+	 */
+	public $name;
+	/**
+	 * @var string raw name of this table. This is the quoted version of table name with optional schema name. It can be directly used in SQLs.
+	 */
+	public $rawName;
+	/**
+	 * @var string|array primary key name of this table. If composite key, an array of key names is returned.
+	 */
+	public $primaryKey;
+	/**
+	 * @var string sequence name for the primary key. Null if no sequence.
+	 */
+	public $sequenceName;
+	/**
+	 * @var array foreign keys of this table. The array is indexed by column name. Each value is an array of foreign table name and foreign column name.
+	 */
+	public $foreignKeys=array();
+	/**
+	 * @var array column metadata of this table. Each array element is a TDbColumnSchema object, indexed by column names.
+	 */
+	public $columns=array();
+
+	/**
+	 * Gets the named column metadata.
+	 * This is a convenient method for retrieving a named column even if it does not exist.
+	 * @param string column name
+	 * @return TDbColumnSchema metadata of the named column. Null if the named column does not exist.
+	 */
+	public function getColumn($name)
+	{
+		return isset($this->columns[$name]) ? $this->columns[$name] : null;
+	}
+
+	/**
+	 * @return array list of column names
+	 */
+	public function getColumnNames()
+	{
+		return array_keys($this->columns);
+	}
+}
diff --git a/framework/Db/Schema/mssql/TMssqlColumnSchema.php b/framework/Db/Schema/mssql/TMssqlColumnSchema.php
new file mode 100755
index 00000000..0c5c6ac4
--- /dev/null
+++ b/framework/Db/Schema/mssql/TMssqlColumnSchema.php
@@ -0,0 +1,57 @@
+<?php
+/**
+ * TMssqlColumnSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbColumnSchema');
+
+/**
+ * TMssqlColumnSchema class describes the column meta data of a MSSQL table.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @version $Id: TMssqlColumnSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.mssql
+ * @since 1.0.4
+ */
+class TMssqlColumnSchema extends TDbColumnSchema
+{
+	/**
+	 * Extracts the PHP type from DB type.
+	 * @param string DB type
+	 */
+	protected function extractType($dbType)
+	{
+		if(strpos($dbType,'bigint')!==false || strpos($dbType,'float')!==false || strpos($dbType,'real')!==false)
+			$this->type='double';
+		else if(strpos($dbType,'int')!==false || strpos($dbType,'smallint')!==false || strpos($dbType,'tinyint'))
+			$this->type='integer';
+		else if(strpos($dbType,'bit')!==false)
+			$this->type='boolean';
+		else
+			$this->type='string';
+	}
+
+	protected function extractDefault($defaultValue)
+	{
+		if($this->dbType==='timestamp' )
+			$this->defaultValue=null;
+		else
+			parent::extractDefault(str_replace(array('(',')',"'"), '', $defaultValue));
+	}
+
+	/**
+	 * Extracts size, precision and scale information from column's DB type.
+	 * We do nothing here, since sizes and precisions have been computed before.
+	 * @param string the column's DB type
+	 */
+	protected function extractLimit($dbType)
+	{
+	}
+}
diff --git a/framework/Db/Schema/mssql/TMssqlCommandBuilder.php b/framework/Db/Schema/mssql/TMssqlCommandBuilder.php
new file mode 100755
index 00000000..f0b5c7f4
--- /dev/null
+++ b/framework/Db/Schema/mssql/TMssqlCommandBuilder.php
@@ -0,0 +1,303 @@
+<?php
+/**
+ * CMsCommandBuilder class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using ('System.Db.schame.TDbCommandBuilder');
+
+/**
+ * TMssqlCommandBuilder provides basic methods to create query commands for tables for Mssql Servers.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @version $Id: TMssqlCommandBuilder.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package system.db.schema.mssql
+ * @since 1.0.4
+ */
+class TMssqlCommandBuilder extends TDbCommandBuilder
+{
+   	/**
+	 * Returns the last insertion ID for the specified table.
+	 * Override parent implemantation since PDO mssql driver does not provide this method
+	 * @param TDbTableSchema the table metadata
+	 * @return mixed last insertion id. Null is returned if no sequence name.
+	 */
+	public function getLastInsertID($table)
+	{
+		if($table->sequenceName!==null)
+			return $this->getDbConnection()->createCommand('SELECT SCOPE_IDENTITY()')->queryScalar();
+		else
+			return null;
+	}
+
+	/**
+	 * Creates a COUNT(*) command for a single table.
+	 * Override parent implementation to remove the order clause of criteria if it exists
+	 * @param TDbTableSchema the table metadata
+	 * @param TDbCriteria the query criteria
+	 * @return TDbCommand query command.
+	 */
+	public function createCountCommand($table,$criteria)
+	{
+		$criteria->order='';
+		return parent::createCountCommand($table, $criteria);
+	}
+
+	/**
+	 * Creates a SELECT command for a single table.
+	 * Override parent implementation to check if an orderby clause if specified when querying with an offset
+	 * @param TDbTableSchema the table metadata
+	 * @param TDbCriteria the query criteria
+	 * @return TDbCommand query command.
+	 */
+	public function createFindCommand($table,$criteria)
+	{
+		$criteria=$this->checkCriteria($table,$criteria);
+		return parent::createFindCommand($table,$criteria);
+
+	}
+
+	/**
+	 * Creates an UPDATE command.
+	 * Override parent implementation because mssql don't want to update an identity column
+	 * @param TDbTableSchema the table metadata
+	 * @param array list of columns to be updated (name=>value)
+	 * @param TDbCriteria the query criteria
+	 * @return TDbCommand update command.
+	 */
+	public function createUpdateCommand($table,$data,$criteria)
+	{
+		$criteria=$this->checkCriteria($table,$criteria);
+		$fields=array();
+		$values=array();
+		$bindByPosition=isset($criteria->params[0]);
+		foreach($data as $name=>$value)
+		{
+			if(($column=$table->getColumn($name))!==null)
+			{
+				if ($table->sequenceName !== null && $column->isPrimaryKey === true) continue;
+				if($value instanceof TDbExpression)
+					$fields[]=$column->rawName.'='.(string)$value;
+				else if($bindByPosition)
+				{
+					$fields[]=$column->rawName.'=?';
+					$values[]=$column->typecast($value);
+				}
+				else
+				{
+					$fields[]=$column->rawName.'=:'.$name;
+					$values[':'.$name]=$column->typecast($value);
+				}
+			}
+		}
+		if($fields===array())
+			throw new TDbException('No columns are being updated for table "{0}".',
+				$table->name);
+		$sql="UPDATE {$table->rawName} SET ".implode(', ',$fields);
+		$sql=$this->applyJoin($sql,$criteria->join);
+		$sql=$this->applyCondition($sql,$criteria->condition);
+		$sql=$this->applyOrder($sql,$criteria->order);
+		$sql=$this->applyLimit($sql,$criteria->limit,$criteria->offset);
+
+		$command=$this->getDbConnection()->createCommand($sql);
+		$this->bindValues($command,array_merge($values,$criteria->params));
+
+		return $command;
+	}
+
+	/**
+	 * Creates a DELETE command.
+	 * Override parent implementation to check if an orderby clause if specified when querying with an offset
+	 * @param TDbTableSchema the table metadata
+	 * @param TDbCriteria the query criteria
+	 * @return TDbCommand delete command.
+	 */
+	public function createDeleteCommand($table,$criteria)
+	{
+		$criteria=$this->checkCriteria($table, $criteria);
+		return parent::createDeleteCommand($table, $criteria);
+	}
+
+	/**
+	 * Creates an UPDATE command that increments/decrements certain columns.
+	 * Override parent implementation to check if an orderby clause if specified when querying with an offset
+	 * @param TDbTableSchema the table metadata
+	 * @param TDbCriteria the query criteria
+	 * @param array counters to be updated (counter increments/decrements indexed by column names.)
+	 * @return TDbCommand the created command
+	 * @throws CException if no counter is specified
+	 */
+	public function createUpdateCounterCommand($table,$counters,$criteria)
+	{
+		$criteria=$this->checkCriteria($table, $criteria);
+		return parent::createUpdateCounterCommand($table, $counters, $criteria);
+	}
+
+	/**
+	 * This is a port from Prado Framework.
+	 *
+	 * Overrides parent implementation. Alters the sql to apply $limit and $offset.
+	 * The idea for limit with offset is done by modifying the sql on the fly
+	 * with numerous assumptions on the structure of the sql string.
+	 * The modification is done with reference to the notes from
+	 * http://troels.arvin.dk/db/rdbms/#select-limit-offset
+	 *
+	 * <code>
+	 * SELECT * FROM (
+	 *  SELECT TOP n * FROM (
+	 *    SELECT TOP z columns      -- (z=n+skip)
+	 *    FROM tablename
+	 *    ORDER BY key ASC
+	 *  ) AS FOO ORDER BY key DESC -- ('FOO' may be anything)
+	 * ) AS BAR ORDER BY key ASC    -- ('BAR' may be anything)
+	 * </code>
+	 *
+	 * <b>Regular expressions are used to alter the SQL query. The resulting SQL query
+	 * may be malformed for complex queries.</b> The following restrictions apply
+	 *
+	 * <ul>
+	 *   <li>
+	 * In particular, <b>commas</b> should <b>NOT</b>
+	 * be used as part of the ordering expression or identifier. Commas must only be
+	 * used for separating the ordering clauses.
+	 *  </li>
+	 *  <li>
+	 * In the ORDER BY clause, the column name should NOT be be qualified
+	 * with a table name or view name. Alias the column names or use column index.
+	 * </li>
+	 * <li>
+	 * No clauses should follow the ORDER BY clause, e.g. no COMPUTE or FOR clauses.
+	 * </li>
+	 *
+	 * @param string SQL query string.
+	 * @param integer maximum number of rows, -1 to ignore limit.
+	 * @param integer row offset, -1 to ignore offset.
+	 * @return string SQL with limit and offset.
+	 *
+	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+	 */
+	public function applyLimit($sql, $limit, $offset)
+	{
+		$limit = $limit!==null ? intval($limit) : -1;
+		$offset = $offset!==null ? intval($offset) : -1;
+		if ($limit > 0 && $offset <= 0) //just limit
+			$sql = preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',"\\1SELECT\\2 TOP $limit", $sql);
+		else if($limit > 0 && $offset > 0)
+			$sql = $this->rewriteLimitOffsetSql($sql, $limit,$offset);
+		return $sql;
+	}
+
+	/**
+	 * Rewrite sql to apply $limit > and $offset > 0 for MSSQL database.
+	 * See http://troels.arvin.dk/db/rdbms/#select-limit-offset
+	 * @param string sql query
+	 * @param integer $limit > 0
+	 * @param integer $offset > 0
+	 * @return sql modified sql query applied with limit and offset.
+	 *
+	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+	 */
+	protected function rewriteLimitOffsetSql($sql, $limit, $offset)
+	{
+		$fetch = $limit+$offset;
+		$sql = preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',"\\1SELECT\\2 TOP $fetch", $sql);
+		$ordering = $this->findOrdering($sql);
+
+		$orginalOrdering = $this->joinOrdering($ordering);
+		$reverseOrdering = $this->joinOrdering($this->reverseDirection($ordering));
+		$sql = "SELECT * FROM (SELECT TOP {$limit} * FROM ($sql) as [__inner top table__] {$reverseOrdering}) as [__outer top table__] {$orginalOrdering}";
+		return $sql;
+	}
+
+	/**
+	 * Base on simplified syntax http://msdn2.microsoft.com/en-us/library/aa259187(SQL.80).aspx
+	 *
+	 * @param string $sql
+	 * @return array ordering expression as key and ordering direction as value
+	 *
+	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+	 */
+	protected function findOrdering($sql)
+	{
+		if(!preg_match('/ORDER BY/i', $sql))
+			return array();
+		$matches=array();
+		$ordering=array();
+		preg_match_all('/(ORDER BY)[\s"\[](.*)(ASC|DESC)?(?:[\s"\[]|$|COMPUTE|FOR)/i', $sql, $matches);
+		if(count($matches)>1 && count($matches[2]) > 0)
+		{
+			$parts = explode(',', $matches[2][0]);
+			foreach($parts as $part)
+			{
+				$subs=array();
+				if(preg_match_all('/(.*)[\s"\]](ASC|DESC)$/i', trim($part), $subs))
+				{
+					if(count($subs) > 1 && count($subs[2]) > 0)
+					{
+						$ordering[$subs[1][0]] = $subs[2][0];
+					}
+					//else what?
+				}
+				else
+					$ordering[trim($part)] = 'ASC';
+			}
+		}
+		return $ordering;
+	}
+
+	/**
+	 * @param array ordering obtained from findOrdering()
+	 * @return string concat the orderings
+	 *
+	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+	 */
+	protected function joinOrdering($orders)
+	{
+		if(count($orders)>0)
+		{
+			$str=array();
+			foreach($orders as $column => $direction)
+				$str[] = $column.' '.$direction;
+			return 'ORDER BY '.implode(', ', $str);
+		}
+	}
+
+	/**
+	 * @param array original ordering
+	 * @return array ordering with reversed direction.
+	 *
+	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+	 */
+	protected function reverseDirection($orders)
+	{
+		foreach($orders as $column => $direction)
+			$orders[$column] = strtolower(trim($direction))==='desc' ? 'ASC' : 'DESC';
+		return $orders;
+	}
+
+
+	/**
+	 * Checks if the criteria has an order by clause when using offset/limit.
+	 * Override parent implementation to check if an orderby clause if specified when querying with an offset
+	 * If not, order it by pk.
+	 * @param TMssqlTableSchema table schema
+	 * @param TDbCriteria criteria
+	 * @return TDbCrireria the modified criteria
+	 */
+	protected function checkCriteria($table, $criteria)
+	{
+		if ($criteria->offset > 0 && $criteria->order==='')
+		{
+			$criteria->order=is_array($table->primaryKey)?implode(',',$table->primaryKey):$table->primaryKey;
+		}
+		return $criteria;
+	}
+}
diff --git a/framework/Db/Schema/mssql/TMssqlPdoAdapter.php b/framework/Db/Schema/mssql/TMssqlPdoAdapter.php
new file mode 100755
index 00000000..c9d4597f
--- /dev/null
+++ b/framework/Db/Schema/mssql/TMssqlPdoAdapter.php
@@ -0,0 +1,74 @@
+<?php
+/**
+ * TMssqlPdo class file
+ *
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+/**
+ * This is an extension of default PDO class for mssql driver only
+ * It provides some missing functionalities of pdo driver
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @version $Id: TMssqlPdoAdapter.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package system.db.schema.mssql
+ * @since 1.0.4
+ */
+class TMssqlPdoAdapter extends PDO
+{
+	/**
+	 * Get the last inserted id value
+	 * MSSQL doesn't support sequence, so, argument is ignored
+	 *
+	 * @param string sequence name. Defaults to null
+	 * @return int last inserted id
+	 */
+	public function lastInsertId ($sequence=NULL)
+	{
+		return $this->query('SELECT SCOPE_IDENTITY()')->fetchColumn();
+	}
+
+	/**
+	 * Begin a transaction
+	 *
+	 * Is is necessary to override pdo's method, as mssql pdo drivers
+	 * does not support transaction
+	 *
+	 * @return boolean
+	 */
+	public function beginTransaction ()
+	{
+		$this->exec('BEGIN TRANSACTION');
+		return true;
+	}
+
+	/**
+	 * Commit a transaction
+	 *
+	 * Is is necessary to override pdo's method, as mssql pdo drivers
+	 * does not support transaction
+	 *
+	 * @return boolean
+	 */
+	public function commit ()
+	{
+		$this->exec('COMMIT TRANSACTION');
+		return true;
+	}
+
+	/**
+	 * Rollback a transaction
+	 *
+	 * Is is necessary to override pdo's method, ac mssql pdo drivers
+	 * does not support transaction
+	 *
+	 * @return boolean
+	 */
+	public function rollBack ()
+	{
+		$this->exec('ROLLBACK TRANSACTION');
+		return true;
+	}
+}
diff --git a/framework/Db/Schema/mssql/TMssqlSchema.php b/framework/Db/Schema/mssql/TMssqlSchema.php
new file mode 100755
index 00000000..063e8994
--- /dev/null
+++ b/framework/Db/Schema/mssql/TMssqlSchema.php
@@ -0,0 +1,312 @@
+<?php
+/**
+ * TMssqlSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbSchema');
+
+/**
+ * TMssqlSchema is the class for retrieving metadata information from a MS SQL Server database.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @version $Id: TMssqlSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.mssql
+ * @since 1.0.4
+ */
+class TMssqlSchema extends TDbSchema
+{
+	const DEFAULT_SCHEMA='dbo';
+
+
+	/**
+	 * Quotes a table name for use in a query.
+	 * @param string table name
+	 * @return string the properly quoted table name
+	 */
+	public function quoteTableName($name)
+	{
+		if (strpos($name,'.')===false)
+			return '['.$name.']';
+		$names=explode('.',$name);
+		foreach ($names as &$n)
+			$n = '['.$n.']';
+		return implode('.',$names);
+	}
+
+	/**
+	 * Quotes a column name for use in a query.
+	 * @param string column name
+	 * @return string the properly quoted column name
+	 */
+	public function quoteColumnName($name)
+	{
+		return '['.$name.']';
+	}
+
+	/**
+	 * Compares two table names.
+	 * The table names can be either quoted or unquoted. This method
+	 * will consider both cases.
+	 * @param string table name 1
+	 * @param string table name 2
+	 * @return boolean whether the two table names refer to the same table.
+	 */
+	public function compareTableNames($name1,$name2)
+	{
+		$name1=str_replace(array('[',']'),'',$name1);
+		$name1=str_replace(array('[',']'),'',$name2);
+		return parent::compareTableNames(strtolower($name1),strtolower($name2));
+	}
+
+	/**
+	 * Creates a table instance representing the metadata for the named table.
+	 * @return CMysqlTableSchema driver dependent table metadata. Null if the table does not exist.
+	 */
+	protected function createTable($name)
+	{
+		$table=new TMssqlTableSchema;
+		$this->resolveTableNames($table,$name);
+		//if (!in_array($table->name, $this->tableNames)) return null;
+		$table->primaryKey=$this->findPrimaryKey($table);
+		$table->foreignKeys=$this->findForeignKeys($table);
+		if($this->findColumns($table))
+		{
+			return $table;
+		}
+		else
+			return null;
+	}
+
+	/**
+	 * Generates various kinds of table names.
+	 * @param CMysqlTableSchema the table instance
+	 * @param string the unquoted table name
+	 */
+	protected function resolveTableNames($table,$name)
+	{
+		$parts=explode('.',str_replace(array('[',']'),'',$name));
+		if(($c=count($parts))==3)
+		{
+			// Catalog name, schema name and table name provided
+			$table->catalogName=$parts[0];
+			$table->schemaName=$parts[1];
+			$table->name=$parts[2];
+			$table->rawName=$this->quoteTableName($table->catalogName).'.'.$this->quoteTableName($table->schemaName).'.'.$this->quoteTableName($table->name);
+		}
+		elseif ($c==2)
+		{
+			// Only schema name and table name provided
+			$table->name=$parts[1];
+			$table->schemaName=$parts[0];
+			$table->rawName=$this->quoteTableName($table->schemaName).'.'.$this->quoteTableName($table->name);
+		}
+		else
+		{
+			// Only the name given, we need to get at least the schema name
+			//if (empty($this->_schemaNames)) $this->findTableNames();
+			$table->name=$parts[0];
+			$table->schemaName=self::DEFAULT_SCHEMA;
+			$table->rawName=$this->quoteTableName($table->schemaName).'.'.$this->quoteTableName($table->name);
+		}
+	}
+
+	/**
+	 * Gets the primary key column(s) details for the given table.
+	 * @param TMssqlTableSchema table
+	 * @return mixed primary keys (null if no pk, string if only 1 column pk, or array if composite pk)
+	 */
+	protected function findPrimaryKey($table)
+	{
+		$kcu='INFORMATION_SCHEMA.KEY_COLUMN_USAGE';
+		$tc='INFORMATION_SCHEMA.TABLE_CONSTRAINTS';
+		if (isset($table->catalogName))
+		{
+			$kcu=$table->catalogName.'.'.$kcu;
+			$tc=$table->catalogName.'.'.$tc;
+		}
+
+		$sql = <<<EOD
+		SELECT k.column_name field_name
+			FROM {$this->quoteTableName($kcu)} k
+		    LEFT JOIN {$this->quoteTableName($tc)} c
+		      ON k.table_name = c.table_name
+		     AND k.constraint_name = c.constraint_name
+		   WHERE c.constraint_type ='PRIMARY KEY'
+		   	    AND k.table_name = :table
+				AND k.table_schema = :schema
+EOD;
+		$command = $this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table', $table->name);
+		$command->bindValue(':schema', $table->schemaName);
+		$primary=$command->queryColumn();
+		switch (count($primary))
+		{
+			case 0: // No primary key on table
+				$primary=null;
+				break;
+			case 1: // Only 1 primary key
+				$primary=$primary[0];
+				break;
+		}
+		return $primary;
+	}
+
+	/**
+	 * Gets foreign relationship constraint keys and table name
+	 * @param TMssqlTableSchema table
+	 * @return array foreign relationship table name and keys.
+	 */
+	protected function findForeignKeys($table)
+	{
+		$rc='INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS';
+		$kcu='INFORMATION_SCHEMA.KEY_COLUMN_USAGE';
+		if (isset($table->catalogName))
+		{
+			$kcu=$table->catalogName.'.'.$kcu;
+			$rc=$table->catalogName.'.'.$rc;
+		}
+
+		//From http://msdn2.microsoft.com/en-us/library/aa175805(SQL.80).aspx
+		$sql = <<<EOD
+		SELECT
+		     KCU1.CONSTRAINT_NAME AS 'FK_CONSTRAINT_NAME'
+		   , KCU1.TABLE_NAME AS 'FK_TABLE_NAME'
+		   , KCU1.COLUMN_NAME AS 'FK_COLUMN_NAME'
+		   , KCU1.ORDINAL_POSITION AS 'FK_ORDINAL_POSITION'
+		   , KCU2.CONSTRAINT_NAME AS 'UQ_CONSTRAINT_NAME'
+		   , KCU2.TABLE_NAME AS 'UQ_TABLE_NAME'
+		   , KCU2.COLUMN_NAME AS 'UQ_COLUMN_NAME'
+		   , KCU2.ORDINAL_POSITION AS 'UQ_ORDINAL_POSITION'
+		FROM {$this->quoteTableName($rc)} RC
+		JOIN {$this->quoteTableName($kcu)} KCU1
+		ON KCU1.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG
+		   AND KCU1.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA
+		   AND KCU1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
+		JOIN {$this->quoteTableName($kcu)} KCU2
+		ON KCU2.CONSTRAINT_CATALOG =
+		RC.UNIQUE_CONSTRAINT_CATALOG
+		   AND KCU2.CONSTRAINT_SCHEMA =
+		RC.UNIQUE_CONSTRAINT_SCHEMA
+		   AND KCU2.CONSTRAINT_NAME =
+		RC.UNIQUE_CONSTRAINT_NAME
+		   AND KCU2.ORDINAL_POSITION = KCU1.ORDINAL_POSITION
+		WHERE KCU1.TABLE_NAME = :table
+EOD;
+		$command = $this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table', $table->name);
+		$fkeys=array();
+		foreach($command->queryAll() as $info)
+		{
+			$fkeys[$info['FK_COLUMN_NAME']]=array($info['UQ_TABLE_NAME'],$info['UQ_COLUMN_NAME'],);
+
+		}
+		return $fkeys;
+	}
+
+
+	/**
+	 * Collects the table column metadata.
+	 * @param CMysqlTableSchema the table metadata
+	 * @return boolean whether the table exists in the database
+	 */
+	protected function findColumns($table)
+	{
+		$where=array();
+		$where[]="TABLE_NAME='".$table->name."'";
+		if (isset($table->catalogName))
+			$where[]="TABLE_CATALOG='".$table->catalogName."'";
+		if (isset($table->schemaName))
+			$where[]="TABLE_SCHEMA='".$table->schemaName."'";
+		$sql="SELECT *, columnproperty(object_id(table_schema+'.'+table_name), column_name, 'IsIdentity') as IsIdentity ".
+			 "FROM INFORMATION_SCHEMA.COLUMNS WHERE ".join(' AND ',$where);
+		if (($columns=$this->getDbConnection()->createCommand($sql)->queryAll())===array())
+			return false;
+
+		foreach($columns as $column)
+		{
+			$c=$this->createColumn($column);
+			if (is_array($table->primaryKey))
+				$c->isPrimaryKey=in_array($c->name, $table->primaryKey);
+			else
+				$c->isPrimaryKey=strcasecmp($c->name,$table->primaryKey)===0;
+
+			$c->isForeignKey=isset($table->foreignKeys[$c->name]);
+			$table->columns[$c->name]=$c;
+			if ($column['IsIdentity']==1 && $table->sequenceName===null)
+				$table->sequenceName='';
+
+		}
+		return true;
+	}
+
+	/**
+	 * Creates a table column.
+	 * @param array column metadata
+	 * @return TDbColumnSchema normalized column metadata
+	 */
+	protected function createColumn($column)
+	{
+		$c=new TMssqlColumnSchema;
+		$c->name=$column['COLUMN_NAME'];
+		$c->rawName=$this->quoteColumnName($c->name);
+		$c->allowNull=$column['IS_NULLABLE']=='YES';
+		if ($column['NUMERIC_PRECISION_RADIX']!==null)
+		{
+			// We have a numeric datatype
+			$c->size=$c->precision=$column['NUMERIC_PRECISION']!==null?(int)$column['NUMERIC_PRECISION']:null;
+			$c->scale=$column['NUMERIC_SCALE']!==null?(int)$column['NUMERIC_SCALE']:null;
+		}
+		elseif ($column['DATA_TYPE']=='image' || $column['DATA_TYPE']=='text')
+			$c->size=$c->precision=null;
+		else
+			$c->size=$c->precision=($column['CHARACTER_MAXIMUM_LENGTH']!== null)?(int)$column['CHARACTER_MAXIMUM_LENGTH']:null;
+
+		$c->init($column['DATA_TYPE'],$column['COLUMN_DEFAULT']);
+		return $c;
+	}
+
+	/**
+	 * Returns all table names in the database.
+	 * @return array all table names in the database.
+	 * @since 1.0.4
+	 */
+	protected function findTableNames($schema='')
+	{
+		if($schema==='')
+			$schema=self::DEFAULT_SCHEMA;
+		$sql=<<<EOD
+SELECT TABLE_NAME, TABLE_SCHEMA FROM [INFORMATION_SCHEMA].[TABLES]
+WHERE TABLE_TYPE='BASE TABLE' AND TABLE_SCHEMA=:schema
+EOD;
+		$command=$this->getDbConnection()->createCommand($sql);
+		$command->bindParam(":schema", $schema);
+		$rows=$command->queryAll();
+		$names=array();
+		foreach ($rows as $row)
+		{
+			if ($schema == self::DEFAULT_SCHEMA)
+				$names[]=$row['TABLE_NAME'];
+			else
+				$names[]=$schema.'.'.$row['TABLE_SCHEMA'].'.'.$row['TABLE_NAME'];
+		}
+
+		return $names;
+	}
+
+	/**
+	 * Creates a command builder for the database.
+	 * This method overrides parent implementation in order to create a MSSQL specific command builder
+	 * @return TDbCommandBuilder command builder instance
+	 */
+	protected function createCommandBuilder()
+	{
+		return new TMssqlCommandBuilder($this);
+	}
+}
diff --git a/framework/Db/Schema/mssql/TMssqlTableSchema.php b/framework/Db/Schema/mssql/TMssqlTableSchema.php
new file mode 100755
index 00000000..ed1b7c8a
--- /dev/null
+++ b/framework/Db/Schema/mssql/TMssqlTableSchema.php
@@ -0,0 +1,35 @@
+<?php
+/**
+ * TMssqlTableSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.TDbTableSchema');
+
+/**
+ * TMssqlTableSchema represents the metadata for a MSSQL table.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @author Christophe Boulain <Christophe.Boulain@gmail.com>
+ * @version $Id: TMssqlTableSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package system.Db.schema.mssql
+ * @since 1.0.4
+ */
+class TMssqlTableSchema extends TDbTableSchema
+{
+	/**
+	 * @var string name of the catalog (database) that this table belongs to.
+	 * Defaults to null, meaning no schema (or the current database).
+	 */
+	public $catalogName;
+	/**
+	 * @var string name of the schema that this table belongs to.
+	 * Defaults to null, meaning no schema (or the current database owner).
+	 */
+	public $schemaName;
+}
diff --git a/framework/Db/Schema/mysql/TMysqlColumnSchema.php b/framework/Db/Schema/mysql/TMysqlColumnSchema.php
new file mode 100755
index 00000000..d3bb230c
--- /dev/null
+++ b/framework/Db/Schema/mysql/TMysqlColumnSchema.php
@@ -0,0 +1,46 @@
+<?php
+/**
+ * TMysqlColumnSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbColumnSchema');
+
+/**
+ * TMysqlColumnSchema class describes the column meta data of a MySQL table.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TMysqlColumnSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.mysql
+ * @since 1.0
+ */
+class TMysqlColumnSchema extends TDbColumnSchema
+{
+	/**
+	 * Extracts the PHP type from DB type.
+	 * @param string DB type
+	 */
+	protected function extractType($dbType)
+	{
+		if(strpos($dbType,'bigint')!==false || strpos($dbType,'float')!==false || strpos($dbType,'double')!==false)
+			$this->type='double';
+		else if(strpos($dbType,'bool')!==false || $dbType==='tinyint(1)')
+			$this->type='boolean';
+		else if(strpos($dbType,'int')!==false || strpos($dbType,'bit')!==false)
+			$this->type='integer';
+		else
+			$this->type='string';
+	}
+
+	protected function extractDefault($defaultValue)
+	{
+		if($this->dbType==='timestamp' && $defaultValue==='CURRENT_TIMESTAMP')
+			$this->defaultValue=null;
+		else
+			parent::extractDefault($defaultValue);
+	}
+}
diff --git a/framework/Db/Schema/mysql/TMysqlSchema.php b/framework/Db/Schema/mysql/TMysqlSchema.php
new file mode 100755
index 00000000..8061e7a8
--- /dev/null
+++ b/framework/Db/Schema/mysql/TMysqlSchema.php
@@ -0,0 +1,205 @@
+<?php
+/**
+ * TMysqlSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbSchema');
+prado::using('System.Db.Schema.mysql.TMysqlTableSchema');
+prado::using('System.Db.Schema.mysql.TMysqlColumnSchema');
+
+/**
+ * TMysqlSchema is the class for retrieving metadata information from a MySQL database (version 4.1.x and 5.x).
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TMysqlSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.mysql
+ * @since 1.0
+ */
+class TMysqlSchema extends TDbSchema
+{
+	private $_tableNames;
+	private $_schemaNames;
+
+	/**
+	 * Quotes a table name for use in a query.
+	 * @param string table name
+	 * @return string the properly quoted table name
+	 */
+	public function quoteTableName($name)
+	{
+		return '`'.$name.'`';
+	}
+
+	/**
+	 * Quotes a column name for use in a query.
+	 * @param string column name
+	 * @return string the properly quoted column name
+	 */
+	public function quoteColumnName($name)
+	{
+		return '`'.$name.'`';
+	}
+
+	/**
+	 * Compares two table names.
+	 * The table names can be either quoted or unquoted. This method
+	 * will consider both cases.
+	 * @param string table name 1
+	 * @param string table name 2
+	 * @return boolean whether the two table names refer to the same table.
+	 */
+	public function compareTableNames($name1,$name2)
+	{
+		return parent::compareTableNames(strtolower($name1),strtolower($name2));
+	}
+
+	/**
+	 * Creates a table instance representing the metadata for the named table.
+	 * @return TMysqlTableSchema driver dependent table metadata. Null if the table does not exist.
+	 */
+	protected function createTable($name)
+	{
+		$table=new TMysqlTableSchema;
+		$this->resolveTableNames($table,$name);
+
+		if($this->findColumns($table))
+		{
+			$this->findConstraints($table);
+			return $table;
+		}
+		else
+			return null;
+	}
+
+	/**
+	 * Generates various kinds of table names.
+	 * @param TMysqlTableSchema the table instance
+	 * @param string the unquoted table name
+	 */
+	protected function resolveTableNames($table,$name)
+	{
+		$parts=explode('.',str_replace('`','',$name));
+		if(isset($parts[1]))
+		{
+			$table->schemaName=$parts[0];
+			$table->name=$parts[1];
+			$table->rawName=$this->quoteTableName($table->schemaName).'.'.$this->quoteTableName($table->name);
+		}
+		else
+		{
+			$table->name=$parts[0];
+			$table->rawName=$this->quoteTableName($table->name);
+		}
+	}
+
+	/**
+	 * Collects the table column metadata.
+	 * @param TMysqlTableSchema the table metadata
+	 * @return boolean whether the table exists in the database
+	 */
+	protected function findColumns($table)
+	{
+		$sql='SHOW COLUMNS FROM '.$table->rawName;
+		try
+		{
+			$columns=$this->getDbConnection()->createCommand($sql)->queryAll();
+		}
+		catch(Exception $e)
+		{
+			return false;
+		}
+		foreach($columns as $column)
+		{
+			$c=$this->createColumn($column);
+			$table->columns[$c->name]=$c;
+			if($c->isPrimaryKey)
+			{
+				if($table->primaryKey===null)
+					$table->primaryKey=$c->name;
+				else if(is_string($table->primaryKey))
+					$table->primaryKey=array($table->primaryKey,$c->name);
+				else
+					$table->primaryKey[]=$c->name;
+				if(strpos(strtolower($column['Extra']),'auto_increment')!==false)
+					$table->sequenceName='';
+			}
+		}
+		return true;
+	}
+
+	/**
+	 * Creates a table column.
+	 * @param array column metadata
+	 * @return TDbColumnSchema normalized column metadata
+	 */
+	protected function createColumn($column)
+	{
+		$c=new TMysqlColumnSchema;
+		$c->name=$column['Field'];
+		$c->rawName=$this->quoteColumnName($c->name);
+		$c->allowNull=$column['Null']==='YES';
+		$c->isPrimaryKey=strpos($column['Key'],'PRI')!==false;
+		$c->isForeignKey=false;
+		$c->init($column['Type'],$column['Default']);
+		return $c;
+	}
+
+	/**
+	 * @return float server version.
+	 */
+	protected function getServerVersion()
+	{
+		$version=$this->getDbConnection()->getAttribute(PDO::ATTR_SERVER_VERSION);
+		$digits=array();
+		preg_match('/(\d+)\.(\d+)\.(\d+)/', $version, $digits);
+		return floatval($digits[1].'.'.$digits[2].$digits[3]);
+	}
+
+	/**
+	 * Collects the foreign key column details for the given table.
+	 * @param TMysqlTableSchema the table metadata
+	 */
+	protected function findConstraints($table)
+	{
+		$row=$this->getDbConnection()->createCommand('SHOW CREATE TABLE '.$table->rawName)->queryRow();
+		$matches=array();
+		$regexp='/FOREIGN KEY\s+\(([^\)]+)\)\s+REFERENCES\s+([^\(^\s]+)\s*\(([^\)]+)\)/mi';
+		foreach($row as $sql)
+		{
+			if(preg_match_all($regexp,$sql,$matches,PREG_SET_ORDER))
+				break;
+		}
+		$foreign = array();
+		foreach($matches as $match)
+		{
+			$keys=array_map('trim',explode(',',str_replace('`','',$match[1])));
+			$fks=array_map('trim',explode(',',str_replace('`','',$match[3])));
+			foreach($keys as $k=>$name)
+			{
+				$table->foreignKeys[$name]=array(str_replace('`','',$match[2]),$fks[$k]);
+				if(isset($table->columns[$name]))
+					$table->columns[$name]->isForeignKey=true;
+			}
+		}
+	}
+
+	/**
+	 * Returns all table names in the database.
+	 * @return array all table names in the database.
+	 * @since 1.0.2
+	 */
+	protected function findTableNames($schema='')
+	{
+		if($schema==='')
+			return $this->getDbConnection()->createCommand('SHOW TABLES')->queryColumn();
+		$names=$this->getDbConnection()->createCommand('SHOW TABLES FROM '.$this->quoteTableName($schema))->queryColumn();
+		foreach($names as &$name)
+			$name=$schema.'.'.$name;
+		return $names;
+	}
+}
diff --git a/framework/Db/Schema/mysql/TMysqlTableSchema.php b/framework/Db/Schema/mysql/TMysqlTableSchema.php
new file mode 100755
index 00000000..8bed3314
--- /dev/null
+++ b/framework/Db/Schema/mysql/TMysqlTableSchema.php
@@ -0,0 +1,26 @@
+<?php
+/**
+ * TMysqlTableSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+prado::using('System.Db.Schema.TDbTableSchema');
+/**
+ * TMysqlTableSchema represents the metadata for a MySQL table.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TMysqlTableSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.mysql
+ * @since 1.0
+ */
+class TMysqlTableSchema extends TDbTableSchema
+{
+	/**
+	 * @var string name of the schema (database) that this table belongs to.
+	 * Defaults to null, meaning no schema (or the current database).
+	 */
+	public $schemaName;
+}
diff --git a/framework/Db/Schema/oci/TOciColumnSchema.php b/framework/Db/Schema/oci/TOciColumnSchema.php
new file mode 100755
index 00000000..d609d14d
--- /dev/null
+++ b/framework/Db/Schema/oci/TOciColumnSchema.php
@@ -0,0 +1,56 @@
+<?php
+/**
+ * TOciColumnSchema class file.
+ *
+ * @author Ricardo Grana <rickgrana@yahoo.com.br>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbColumnSchema');
+
+/**
+ * TOciColumnSchema class describes the column meta data of a Oracle table.
+ *
+ * @author Ricardo Grana <rickgrana@yahoo.com.br>
+ * @version $Id: TOciColumnSchema.php
+ * @package System.Db.Schema.oci
+ * @since 1.0.5
+ */
+class TOciColumnSchema extends TDbColumnSchema
+{
+	/**
+	 * Extracts the PHP type from DB type.
+	 * @param string DB type
+	 */
+	protected function extractOraType($dbType){
+		if(strpos($dbType,'FLOAT')!==false) return 'double';
+
+		if ((strpos($dbType,'NUMBER')!==false) or
+			(strpos($dbType,'INTEGER')!==false))
+		{
+			if(strpos($dbType,'(') && preg_match('/\((.*)\)/',$dbType,$matches))
+			{
+				$values=explode(',',$matches[1]);
+				if(isset($values[1]) and (((int)$values[1]) > 0))
+					return 'double';
+				else return 'integer';
+			}
+		}else{
+			return 'string';
+		}
+	}
+	protected function extractType($dbType)
+	{
+		$this->type=$this->extractOraType($dbType);
+	}
+
+	protected function extractDefault($defaultValue)
+	{
+		if(strpos($dbType,'timestamp')!==false)
+			$this->defaultValue=null;
+		else
+			parent::extractDefault($defaultValue);
+	}
+}
diff --git a/framework/Db/Schema/oci/TOciCommandBuilder.php b/framework/Db/Schema/oci/TOciCommandBuilder.php
new file mode 100755
index 00000000..807b7271
--- /dev/null
+++ b/framework/Db/Schema/oci/TOciCommandBuilder.php
@@ -0,0 +1,122 @@
+<?php
+/**
+ * TOciCommandBuilder class file.
+ *
+ * @author Ricardo Grana <rickgrana@yahoo.com.br>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbCommandBuilder');
+
+/**
+ * TOciCommandBuilder provides basic methods to create query commands for tables.
+ *
+ * @author Ricardo Grana <rickgrana@yahoo.com.br>
+ * @version $Id: TOciCommandBuilder.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.oci
+ * @since 1.0.5
+ */
+class TOciCommandBuilder extends TDbCommandBuilder
+{
+	/**
+	 * @var integer the last insertion ID
+	 */
+	public $returnID;
+
+	/**
+	 * Returns the last insertion ID for the specified table.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @return mixed last insertion id. Null is returned if no sequence name.
+	 */
+	public function getLastInsertID($table)
+	{
+		return $this->returnID;
+	}
+
+	/**
+	 * Alters the SQL to apply LIMIT and OFFSET.
+	 * Default implementation is applicable for PostgreSQL, MySQL and SQLite.
+	 * @param string SQL query string without LIMIT and OFFSET.
+	 * @param integer maximum number of rows, -1 to ignore limit.
+	 * @param integer row offset, -1 to ignore offset.
+	 * @return string SQL with LIMIT and OFFSET
+	 */
+	public function applyLimit($sql,$limit,$offset)
+	{
+		if (($limit < 0) and ($offset < 0)) return $sql;
+
+		$filters = array();
+		if($offset>0){
+			$filters[] = 'rowNumId >= '.(int)$offset;
+		}
+
+		if($limit>=0){
+			$filters[]= 'rownum <= '.(int)$limit;
+		}
+
+		if (count($filters) > 0){
+			$filter = implode(' and ', $filters);
+			$filter= " WHERE ".$filter;
+		}else{
+			$filter = '';
+		}
+
+
+		$sql = <<<EOD
+				WITH USER_SQL AS ({$sql}),
+				   PAGINATION AS (SELECT USER_SQL.*, rownum as rowNumId FROM USER_SQL)
+				SELECT *
+				FROM PAGINATION
+				{$filter}
+EOD;
+
+		return $sql;
+	}
+
+	/**
+	 * Creates an INSERT command.
+	 * @param mixed the table schema ({@link TDbTableSchema}) or the table name (string).
+	 * @param array data to be inserted (column name=>column value). If a key is not a valid column name, the corresponding value will be ignored.
+	 * @return TDbCommand insert command
+	 */
+	public function createInsertCommand($table,$data)
+	{
+		$this->ensureTable($table);
+		$fields=array();
+		$values=array();
+		$placeholders=array();
+		foreach($data as $name=>$value)
+		{
+			if(($column=$table->getColumn($name))!==null && ($value!==null || $column->allowNull))
+			{
+				$fields[]=$column->rawName;
+				if($value instanceof TDbExpression)
+					$placeholders[]=(string)$value;
+				else
+				{
+					$placeholders[]=':'.$name;
+					$values[':'.$name]=$column->typecast($value);
+				}
+			}
+		}
+
+		$sql="INSERT INTO {$table->rawName} (".implode(', ',$fields).') VALUES ('.implode(', ',$placeholders).')';
+
+		if(is_string($table->primaryKey))
+		{
+			$sql.=" RETURNING ".$table->primaryKey." INTO :RETURN_ID";
+			$command=$this->getDbConnection()->createCommand($sql);
+			$command->bindParam(':RETURN_ID', $this->returnID, PDO::PARAM_INT, 12);
+			$table->sequenceName='RETURN_ID';
+		}
+		else
+			$command=$this->getDbConnection()->createCommand($sql);
+
+		foreach($values as $name=>$value)
+			$command->bindValue($name,$value);
+
+		return $command;
+	}
+}
diff --git a/framework/Db/Schema/oci/TOciSchema.php b/framework/Db/Schema/oci/TOciSchema.php
new file mode 100755
index 00000000..50de0626
--- /dev/null
+++ b/framework/Db/Schema/oci/TOciSchema.php
@@ -0,0 +1,278 @@
+<?php
+/**
+ * TOciSchema class file.
+ *
+ * @author Ricardo Grana <rickgrana@yahoo.com.br>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbSchema');
+
+/**
+ * TOciSchema is the class for retrieving metadata information from a PostgreSQL database.
+ *
+ * @author Ricardo Grana <qiang.xue@gmail.com>
+ * @version $Id: TOciSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.oci
+ * @since 1.0.5
+ */
+class TOciSchema extends TDbSchema
+{
+	private $_defaultSchema = '';
+	private $_sequences=array();
+
+	/**
+	 * Quotes a table name for use in a query.
+	 * @param string table name
+	 * @return string the properly quoted table name
+	 */
+	public function quoteTableName($name)
+	{
+		return $name;
+	}
+
+	/**
+	 * Quotes a column name for use in a query.
+	 * @param string column name
+	 * @return string the properly quoted column name
+	 */
+	public function quoteColumnName($name)
+	{
+		return $name;
+	}
+
+	/**
+	 * Creates a command builder for the database.
+	 * This method may be overridden by child classes to create a DBMS-specific command builder.
+	 * @return TDbCommandBuilder command builder instance
+	 */
+	protected function createCommandBuilder()
+	{
+		return new TOciCommandBuilder($this);
+	}
+
+	/**
+     * @param string default schema.
+     */
+    public function setDefaultSchema($schema)
+    {
+		$this->_defaultSchema=$schema;
+    }
+
+    /**
+     * @return string default schema.
+     */
+    public function getDefaultSchema()
+    {
+		if (!strlen($this->_defaultSchema))
+		{
+			$this->setDefaultSchema(strtoupper($this->getDbConnection()->username));
+		}
+
+		return $this->_defaultSchema;
+    }
+
+    /**
+     * @param string table name with optional schema name prefix, uses default schema name prefix is not provided.
+     * @return array tuple as ($schemaName,$tableName)
+     */
+    protected function getSchemaTableName($table)
+    {
+		$table = strtoupper($table);
+		if(count($parts= explode('.', str_replace('"','',$table))) > 1)
+			return array($parts[0], $parts[1]);
+		else
+			return array($this->getDefaultSchema(),$parts[0]);
+    }
+
+	/**
+	 * Creates a table instance representing the metadata for the named table.
+	 * @return TDbTableSchema driver dependent table metadata.
+	 */
+	protected function createTable($name)
+	{
+		$table=new TOciTableSchema;
+		$this->resolveTableNames($table,$name);
+
+		if(!$this->findColumns($table))
+			return null;
+		$this->findConstraints($table);
+
+		return $table;
+	}
+
+	/**
+	 * Generates various kinds of table names.
+	 * @param TOciTableSchema the table instance
+	 * @param string the unquoted table name
+	 */
+	protected function resolveTableNames($table,$name)
+	{
+		$parts=explode('.',str_replace('"','',$name));
+		if(isset($parts[1]))
+		{
+			$schemaName=$parts[0];
+			$tableName=$parts[1];
+		}
+		else
+		{
+			$schemaName=$this->getDefaultSchema();
+			$tableName=$parts[0];
+		}
+
+		$table->name=$tableName;
+		$table->schemaName=$schemaName;
+		if($schemaName===$this->getDefaultSchema())
+			$table->rawName=$this->quoteTableName($tableName);
+		else
+			$table->rawName=$this->quoteTableName($schemaName).'.'.$this->quoteTableName($tableName);
+	}
+
+	/**
+	 * Collects the table column metadata.
+	 * @param TOciTableSchema the table metadata
+	 * @return boolean whether the table exists in the database
+	 */
+	protected function findColumns($table)
+	{
+		list($schemaName,$tableName) = $this->getSchemaTableName($table->name);
+
+		$sql=<<<EOD
+SELECT a.column_name, a.data_type ||
+    case
+        when data_precision is not null
+            then '(' || a.data_precision ||
+                    case when a.data_scale > 0 then ',' || a.data_scale else '' end
+                || ')'
+        when data_type = 'DATE' then ''
+        else '(' || to_char(a.data_length) || ')'
+    end as data_type,
+    a.nullable, a.data_default,
+    (   SELECT D.constraint_type
+        FROM ALL_CONS_COLUMNS C
+        inner join ALL_constraints D on D.OWNER = C.OWNER and D.constraint_name = C.constraint_name
+        WHERE C.OWNER = B.OWNER
+           and C.table_name = B.object_name
+           and C.column_name = A.column_name
+           and D.constraint_type = 'P') as Key
+FROM ALL_TAB_COLUMNS A
+inner join ALL_OBJECTS B ON b.owner = a.owner and ltrim(B.OBJECT_NAME) = ltrim(A.TABLE_NAME)
+WHERE
+    a.owner = '{$schemaName}'
+	and b.object_type = 'TABLE'
+	and b.object_name = '{$tableName}'
+ORDER by a.column_id
+EOD;
+
+		$command=$this->getDbConnection()->createCommand($sql);
+
+		if(($columns=$command->queryAll())===array()){
+			return false;
+		}
+
+		foreach($columns as $column)
+		{
+			$c=$this->createColumn($column);
+
+			$table->columns[$c->name]=$c;
+			if($c->isPrimaryKey)
+			{
+				if($table->primaryKey===null)
+					$table->primaryKey=$c->name;
+				else if(is_string($table->primaryKey))
+					$table->primaryKey=array($table->primaryKey,$c->name);
+				else
+					$table->primaryKey[]=$c->name;
+			}
+		}
+		return true;
+	}
+
+	/**
+	 * Creates a table column.
+	 * @param array column metadata
+	 * @return TDbColumnSchema normalized column metadata
+	 */
+	protected function createColumn($column)
+	{
+		$c=new TOciColumnSchema;
+		$c->name=$column['COLUMN_NAME'];
+		$c->rawName=$this->quoteColumnName($c->name);
+		$c->allowNull=$column['NULLABLE']==='Y';
+		$c->isPrimaryKey=strpos($column['KEY'],'P')!==false;
+		$c->isForeignKey=false;
+		$c->init($column['DATA_TYPE'],$column['DATA_DEFAULT']);
+
+		return $c;
+	}
+
+	/**
+	 * Collects the primary and foreign key column details for the given table.
+	 * @param TOciTableSchema the table metadata
+	 */
+	protected function findConstraints($table)
+	{
+		$sql=<<<EOD
+		SELECT D.constraint_type, C.COLUMN_NAME, C.position, D.r_constraint_name,
+                E.table_name as table_ref, f.column_name as column_ref
+        FROM ALL_CONS_COLUMNS C
+        inner join ALL_constraints D on D.OWNER = C.OWNER and D.constraint_name = C.constraint_name
+        left join ALL_constraints E on E.OWNER = D.r_OWNER and E.constraint_name = D.r_constraint_name
+        left join ALL_cons_columns F on F.OWNER = E.OWNER and F.constraint_name = E.constraint_name and F.position = c.position
+        WHERE C.OWNER = '{$table->schemaName}'
+           and C.table_name = '{$table->name}'
+           and D.constraint_type <> 'P'
+        order by d.constraint_name, c.position
+EOD;
+		$command=$this->getDbConnection()->createCommand($sql);
+		foreach($command->queryAll() as $row)
+		{
+			if($row['constraint_type']==='R')   // foreign key
+			{
+				$name = $row["COLUMN_NAME"];
+				$table->foreignKeys[$name]=array($row["TABLE_REF"], array($row["COLUMN_REF"]));
+				if(isset($table->columns[$name]))
+					$table->columns[$name]->isForeignKey=true;
+			}
+
+		}
+	}
+
+
+	/**
+	 * Returns all table names in the database.
+	 * @return array all table names in the database.
+	 */
+	protected function findTableNames($schema='')
+	{
+		if($schema==='')
+		{
+			$sql=<<<EOD
+SELECT table_name, '{$schema}' as table_schema FROM user_tables
+EOD;
+			$command=$this->getDbConnection()->createCommand($sql);
+		}
+		else
+		{
+			$sql=<<<EOD
+SELECT object_name as table_name, owner as table_schema FROM all_objects
+WHERE object_type = 'TABLE' AND owner=:schema
+EOD;
+			$command=$this->getDbConnection()->createCommand($sql);
+			$command->bindParam(':schema',$schema);
+		}
+
+		$rows=$command->queryAll();
+		$names=array();
+		foreach($rows as $row)
+		{
+			if($schema===$this->getDefaultSchema())
+				$names[]=$row['table_name'];
+			else
+				$names[]=$row['schema_name'].'.'.$row['table_name'];
+		}
+		return $names;
+	}
+}
diff --git a/framework/Db/Schema/oci/TOciTableSchema.php b/framework/Db/Schema/oci/TOciTableSchema.php
new file mode 100755
index 00000000..9fe73624
--- /dev/null
+++ b/framework/Db/Schema/oci/TOciTableSchema.php
@@ -0,0 +1,28 @@
+<?php
+/**
+ * TOciTableSchema class file.
+ *
+ * @author Ricardo Grana <rickgrana@yahoo.com.br>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbTableSchame');
+
+/**
+ * TOciTableSchema represents the metadata for a Ora table.
+ *
+ * @author Ricardo Grana <rickgrana@yahoo.com.br>
+ * @version $Id: TOciTableSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.oci
+ * @since 1.0.5
+ */
+class TOciTableSchema extends TDbTableSchema
+{
+	/**
+	 * @var string name of the schema (database) that this table belongs to.
+	 * Defaults to null, meaning no schema (or the current database).
+	 */
+	public $schemaName;
+}
diff --git a/framework/Db/Schema/pgsql/TPgsqlColumnSchema.php b/framework/Db/Schema/pgsql/TPgsqlColumnSchema.php
new file mode 100755
index 00000000..3677cd44
--- /dev/null
+++ b/framework/Db/Schema/pgsql/TPgsqlColumnSchema.php
@@ -0,0 +1,58 @@
+<?php
+/**
+ * TPgsqlColumnSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbColumnSchema');
+
+/**
+ * TPgsqlColumnSchema class describes the column meta data of a PostgreSQL table.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TPgsqlColumnSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.pgsql
+ * @since 1.0
+ */
+class TPgsqlColumnSchema extends TDbColumnSchema
+{
+	/**
+	 * Extracts the PHP type from DB type.
+	 * @param string DB type
+	 */
+	protected function extractType($dbType)
+	{
+		if(strpos($dbType,'integer')!==false || strpos($dbType,'oid')===0)
+			$this->type='integer';
+		else if(strpos($dbType,'bool')!==false)
+			$this->type='boolean';
+		else if(preg_match('/(real|float|double)/',$dbType))
+			$this->type='double';
+		else
+			$this->type='string';
+	}
+
+	/**
+	 * Extracts the default value for the column.
+	 * The value is typecasted to correct PHP type.
+	 * @param mixed the default value obtained from metadata
+	 */
+	protected function extractDefault($defaultValue)
+	{
+		if($defaultValue==='true')
+			$this->defaultValue=true;
+		else if($defaultValue==='false')
+			$this->defaultValue=false;
+		else if(strpos($defaultValue,'nextval')===0)
+			$this->defaultValue=null;
+		else if(preg_match('/\'(.*)\'::/',$defaultValue,$matches))
+			$this->defaultValue=$this->typecast(str_replace("''","'",$matches[1]));
+		else if(preg_match('/^-?\d+(\.\d*)?$/',$defaultValue,$matches))
+			$this->defaultValue=$this->typecast($defaultValue);
+		// else is null
+	}
+}
diff --git a/framework/Db/Schema/pgsql/TPgsqlSchema.php b/framework/Db/Schema/pgsql/TPgsqlSchema.php
new file mode 100755
index 00000000..5f009208
--- /dev/null
+++ b/framework/Db/Schema/pgsql/TPgsqlSchema.php
@@ -0,0 +1,284 @@
+<?php
+/**
+ * TPgsqlSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbSchema');
+
+/**
+ * TPgsqlSchema is the class for retrieving metadata information from a PostgreSQL database.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TPgsqlSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.pgsql
+ * @since 1.0
+ */
+class TPgsqlSchema extends TDbSchema
+{
+	const DEFAULT_SCHEMA='public';
+	private $_sequences=array();
+
+	/**
+	 * Quotes a table name for use in a query.
+	 * @param string table name
+	 * @return string the properly quoted table name
+	 */
+	public function quoteTableName($name)
+	{
+		return '"'.$name.'"';
+	}
+
+	/**
+	 * Creates a table instance representing the metadata for the named table.
+	 * @return TDbTableSchema driver dependent table metadata.
+	 */
+	protected function createTable($name)
+	{
+		$table=new TPgsqlTableSchema;
+		$this->resolveTableNames($table,$name);
+		if(!$this->findColumns($table))
+			return null;
+		$this->findConstraints($table);
+
+		if(is_string($table->primaryKey) && isset($this->_sequences[$table->primaryKey]))
+			$table->sequenceName=$this->_sequences[$table->primaryKey];
+
+		return $table;
+	}
+
+	/**
+	 * Generates various kinds of table names.
+	 * @param TPgsqlTableSchema the table instance
+	 * @param string the unquoted table name
+	 */
+	protected function resolveTableNames($table,$name)
+	{
+		$parts=explode('.',str_replace('"','',$name));
+		if(isset($parts[1]))
+		{
+			$schemaName=$parts[0];
+			$tableName=$parts[1];
+		}
+		else
+		{
+			$schemaName=self::DEFAULT_SCHEMA;
+			$tableName=$parts[0];
+		}
+
+		$table->name=$tableName;
+		$table->schemaName=$schemaName;
+		if($schemaName===self::DEFAULT_SCHEMA)
+			$table->rawName=$this->quoteTableName($tableName);
+		else
+			$table->rawName=$this->quoteTableName($schemaName).'.'.$this->quoteTableName($tableName);
+	}
+
+	/**
+	 * Collects the table column metadata.
+	 * @param TPgsqlTableSchema the table metadata
+	 * @return boolean whether the table exists in the database
+	 */
+	protected function findColumns($table)
+	{
+		$sql=<<<EOD
+SELECT a.attname, LOWER(format_type(a.atttypid, a.atttypmod)) AS type, d.adsrc, a.attnotnull, a.atthasdef
+FROM pg_attribute a LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum
+WHERE a.attnum > 0 AND NOT a.attisdropped
+	AND a.attrelid = (SELECT oid FROM pg_catalog.pg_class WHERE relname=:table
+		AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace WHERE nspname = :schema))
+ORDER BY a.attnum
+EOD;
+		$command=$this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table',$table->name);
+		$command->bindValue(':schema',$table->schemaName);
+
+		if(($columns=$command->queryAll())===array())
+			return false;
+
+		foreach($columns as $column)
+		{
+			$c=$this->createColumn($column);
+			$table->columns[$c->name]=$c;
+
+			if(stripos($column['adsrc'],'nextval')===0 && preg_match('/nextval\([^\']*\'([^\']+)\'[^\)]*\)/i',$column['adsrc'],$matches))
+			{
+				if(strpos($matches[1],'.')!==false || $table->schemaName===self::DEFAULT_SCHEMA)
+					$this->_sequences[$c->name]=$matches[1];
+				else
+					$this->_sequences[$c->name]=$table->schemaName.'.'.$matches[1];
+			}
+		}
+		return true;
+	}
+
+	/**
+	 * Creates a table column.
+	 * @param array column metadata
+	 * @return TDbColumnSchema normalized column metadata
+	 */
+	protected function createColumn($column)
+	{
+		$c=new TPgsqlColumnSchema;
+		$c->name=$column['attname'];
+		$c->rawName=$this->quoteColumnName($c->name);
+		$c->allowNull=!$column['attnotnull'];
+		$c->isPrimaryKey=false;
+		$c->isForeignKey=false;
+
+		$c->init($column['type'],$column['atthasdef'] ? $column['adsrc'] : null);
+
+		return $c;
+	}
+
+	/**
+	 * Collects the primary and foreign key column details for the given table.
+	 * @param TPgsqlTableSchema the table metadata
+	 */
+	protected function findConstraints($table)
+	{
+		$sql=<<<EOD
+SELECT conname, consrc, contype, indkey FROM (
+	SELECT
+		conname,
+		CASE WHEN contype='f' THEN
+			pg_catalog.pg_get_constraintdef(oid)
+		ELSE
+			'CHECK (' || consrc || ')'
+		END AS consrc,
+		contype,
+		conrelid AS relid,
+		NULL AS indkey
+	FROM
+		pg_catalog.pg_constraint
+	WHERE
+		contype IN ('f', 'c')
+	UNION ALL
+	SELECT
+		pc.relname,
+		NULL,
+		CASE WHEN indisprimary THEN
+				'p'
+		ELSE
+				'u'
+		END,
+		pi.indrelid,
+		indkey
+	FROM
+		pg_catalog.pg_class pc,
+		pg_catalog.pg_index pi
+	WHERE
+		pc.oid=pi.indexrelid
+		AND EXISTS (
+			SELECT 1 FROM pg_catalog.pg_depend d JOIN pg_catalog.pg_constraint c
+			ON (d.refclassid = c.tableoid AND d.refobjid = c.oid)
+			WHERE d.classid = pc.tableoid AND d.objid = pc.oid AND d.deptype = 'i' AND c.contype IN ('u', 'p')
+	)
+) AS sub
+WHERE relid = (SELECT oid FROM pg_catalog.pg_class WHERE relname=:table
+	AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace
+	WHERE nspname=:schema))
+EOD;
+		$command=$this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table',$table->name);
+		$command->bindValue(':schema',$table->schemaName);
+		foreach($command->queryAll() as $row)
+		{
+			if($row['contype']==='p') // primary key
+				$this->findPrimaryKey($table,$row['indkey']);
+			else if($row['contype']==='f') // foreign key
+				$this->findForeignKey($table,$row['consrc']);
+		}
+	}
+
+	/**
+	 * Collects primary key information.
+	 * @param TPgsqlTableSchema the table metadata
+	 * @param string pgsql primary key index list
+	 */
+	protected function findPrimaryKey($table,$indices)
+	{
+		$indices=implode(', ',preg_split('/\s+/',$indices));
+		$sql=<<<EOD
+SELECT attnum, attname FROM pg_catalog.pg_attribute WHERE
+	attrelid=(
+		SELECT oid FROM pg_catalog.pg_class WHERE relname=:table AND relnamespace=(
+			SELECT oid FROM pg_catalog.pg_namespace WHERE nspname=:schema
+		)
+	)
+    AND attnum IN ({$indices})
+EOD;
+		$command=$this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table',$table->name);
+		$command->bindValue(':schema',$table->schemaName);
+		foreach($command->queryAll() as $row)
+		{
+			$name=$row['attname'];
+			if(isset($table->columns[$name]))
+			{
+				$table->columns[$name]->isPrimaryKey=true;
+				if($table->primaryKey===null)
+					$table->primaryKey=$name;
+				else if(is_string($table->primaryKey))
+					$table->primaryKey=array($table->primaryKey,$name);
+				else
+					$table->primaryKey[]=$name;
+			}
+		}
+	}
+
+	/**
+	 * Collects foreign key information.
+	 * @param TPgsqlTableSchema the table metadata
+	 * @param string pgsql foreign key definition
+	 */
+	protected function findForeignKey($table,$src)
+	{
+		$matches=array();
+		$brackets='\(([^\)]+)\)';
+		$pattern="/FOREIGN\s+KEY\s+{$brackets}\s+REFERENCES\s+([^\(]+){$brackets}/i";
+		if(preg_match($pattern,str_replace('"','',$src),$matches))
+		{
+			$keys=preg_split('/,\s+/', $matches[1]);
+			$tableName=$matches[2];
+			$fkeys=preg_split('/,\s+/', $matches[3]);
+			foreach($keys as $i=>$key)
+			{
+				$table->foreignKeys[$key]=array($tableName,$fkeys[$i]);
+				if(isset($table->columns[$key]))
+					$table->columns[$key]->isForeignKey=true;
+			}
+		}
+	}
+
+	/**
+	 * Returns all table names in the database.
+	 * @return array all table names in the database.
+	 * @since 1.0.2
+	 */
+	protected function findTableNames($schema='')
+	{
+		if($schema==='')
+			$schema=self::DEFAULT_SCHEMA;
+		$sql=<<<EOD
+SELECT table_name, table_schema FROM information_schema.tables
+WHERE table_schema=:schema
+EOD;
+		$command=$this->getDbConnection()->createCommand($sql);
+		$command->bindParam(':schema',$schema);
+		$rows=$command->queryAll();
+		$names=array();
+		foreach($rows as $row)
+		{
+			if($schema===self::DEFAULT_SCHEMA)
+				$names[]=$row['table_name'];
+			else
+				$names[]=$row['schema_name'].'.'.$row['table_name'];
+		}
+		return $names;
+	}
+}
diff --git a/framework/Db/Schema/pgsql/TPgsqlTableSchema.php b/framework/Db/Schema/pgsql/TPgsqlTableSchema.php
new file mode 100755
index 00000000..9c14da28
--- /dev/null
+++ b/framework/Db/Schema/pgsql/TPgsqlTableSchema.php
@@ -0,0 +1,27 @@
+<?php
+/**
+ * TPgsqlTable class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbTableSchema');
+
+/**
+ * TPgsqlTable represents the metadata for a PostgreSQL table.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TPgsqlTableSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.pgsql
+ * @since 1.0
+ */
+class TPgsqlTableSchema extends TDbTableSchema
+{
+	/**
+	 * @var string name of the schema that this table belongs to.
+	 */
+	public $schemaName;
+}
diff --git a/framework/Db/Schema/sqlite/TSqliteColumnSchema.php b/framework/Db/Schema/sqlite/TSqliteColumnSchema.php
new file mode 100755
index 00000000..ca6858eb
--- /dev/null
+++ b/framework/Db/Schema/sqlite/TSqliteColumnSchema.php
@@ -0,0 +1,35 @@
+<?php
+/**
+ * TSqliteColumnSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbColumnSchema');
+
+/**
+ * TSqliteColumnSchema class describes the column meta data of a SQLite table.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TSqliteColumnSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.sqlite
+ * @since 1.0
+ */
+class TSqliteColumnSchema extends TDbColumnSchema
+{
+	/**
+	 * Extracts the default value for the column.
+	 * The value is typecasted to correct PHP type.
+	 * @param mixed the default value obtained from metadata
+	 */
+	protected function extractDefault($defaultValue)
+	{
+		if($this->type==='string') // PHP 5.2.6 adds single quotes while 5.2.0 doesn't
+			$this->defaultValue=trim($defaultValue,"'\"");
+		else
+			$this->defaultValue=$this->typecast($defaultValue);
+	}
+}
diff --git a/framework/Db/Schema/sqlite/TSqliteCommandBuilder.php b/framework/Db/Schema/sqlite/TSqliteCommandBuilder.php
new file mode 100755
index 00000000..69ffd8a8
--- /dev/null
+++ b/framework/Db/Schema/sqlite/TSqliteCommandBuilder.php
@@ -0,0 +1,43 @@
+<?php
+/**
+ * TSqliteCommandBuilder class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbCommandBuilder');
+
+/**
+ * TSqliteCommandBuilder provides basic methods to create query commands for SQLite tables.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TSqliteCommandBuilder.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.sqlite
+ * @since 1.0
+ */
+class TSqliteCommandBuilder extends TDbCommandBuilder
+{
+	/**
+	 * Generates the expression for selecting rows with specified composite key values.
+	 * This method is overridden because SQLite does not support the default
+	 * IN expression with composite columns.
+	 * @param TDbTableSchema the table schema
+	 * @param array list of primary key values to be selected within
+	 * @param string column prefix (ended with dot)
+	 * @return string the expression for selection
+	 * @since 1.0.4
+	 */
+	protected function createCompositeInCondition($table,$values,$prefix)
+	{
+		$keyNames=array();
+		foreach(array_keys($values[0]) as $name)
+			$keyNames[]=$prefix.$table->columns[$name]->rawName;
+		$vs=array();
+		foreach($values as $value)
+			$vs[]=implode("||','||",$value);
+		return implode("||','||",$keyNames).' IN ('.implode(', ',$vs).')';
+	}
+}
diff --git a/framework/Db/Schema/sqlite/TSqliteSchema.php b/framework/Db/Schema/sqlite/TSqliteSchema.php
new file mode 100755
index 00000000..0e3d4f9a
--- /dev/null
+++ b/framework/Db/Schema/sqlite/TSqliteSchema.php
@@ -0,0 +1,134 @@
+<?php
+/**
+ * TSqliteSchema class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2009 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+prado::using('System.Db.Schema.TDbSchema');
+prado::using('System.Db.Schema.TDbTableSchema');
+prado::using('System.Db.Schema.sqlite.TSqliteColumnSchema');
+prado::using('System.Db.Schema.sqlite.TSqliteCommandBuilder');
+
+/**
+ * TSqliteSchema is the class for retrieving metadata information from a SQLite (2/3) database.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id: TSqliteSchema.php 2679 2009-06-15 07:49:42Z Christophe.Boulain $
+ * @package System.Db.Schema.sqlite
+ * @since 1.0
+ */
+class TSqliteSchema extends TDbSchema
+{
+	/**
+	 * Returns all table names in the database.
+	 * @param string the schema of the tables. This is not used for sqlite database.
+	 * @return array all table names in the database.
+	 * @since 1.0.2
+	 */
+	protected function findTableNames($schema='')
+	{
+		$sql="SELECT DISTINCT tbl_name FROM sqlite_master WHERE tbl_name<>'sqlite_sequence'";
+		return $this->getDbConnection()->createCommand($sql)->queryColumn();
+	}
+
+	/**
+	 * Creates a command builder for the database.
+	 * @return TSqliteCommandBuilder command builder instance
+	 */
+	protected function createCommandBuilder()
+	{
+		return new TSqliteCommandBuilder($this);
+	}
+
+	/**
+	 * Creates a table instance representing the metadata for the named table.
+	 * @return TDbTableSchema driver dependent table metadata. Null if the table does not exist.
+	 */
+	protected function createTable($name)
+	{
+		$db=$this->getDbConnection();
+
+		$table=new TDbTableSchema;
+		$table->name=$name;
+		$table->rawName=$this->quoteTableName($name);
+
+		if($this->findColumns($table))
+		{
+			$this->findConstraints($table);
+			return $table;
+		}
+		else
+			return null;
+	}
+
+	/**
+	 * Collects the table column metadata.
+	 * @param TDbTableSchema the table metadata
+	 * @return boolean whether the table exists in the database
+	 */
+	protected function findColumns($table)
+	{
+		$sql="PRAGMA table_info({$table->rawName})";
+		$columns=$this->getDbConnection()->createCommand($sql)->queryAll();
+		if(empty($columns))
+			return false;
+
+		foreach($columns as $column)
+		{
+			$c=$this->createColumn($column);
+			$table->columns[$c->name]=$c;
+			if($c->isPrimaryKey)
+			{
+				if($table->primaryKey===null)
+					$table->primaryKey=$c->name;
+				else if(is_string($table->primaryKey))
+					$table->primaryKey=array($table->primaryKey,$c->name);
+				else
+					$table->primaryKey[]=$c->name;
+			}
+		}
+		if(is_string($table->primaryKey) && !strncasecmp($table->columns[$table->primaryKey]->dbType,'int',3))
+			$table->sequenceName='';
+
+		return true;
+	}
+
+	/**
+	 * Collects the foreign key column details for the given table.
+	 * @param TDbTableSchema the table metadata
+	 */
+	protected function findConstraints($table)
+	{
+		$foreignKeys=array();
+		$sql="PRAGMA foreign_key_list({$table->rawName})";
+		$keys=$this->getDbConnection()->createCommand($sql)->queryAll();
+		foreach($keys as $key)
+		{
+			$column=$table->columns[$key['from']];
+			$column->isForeignKey=true;
+			$foreignKeys[$key['from']]=array($key['table'],$key['to']);
+		}
+		$table->foreignKeys=$foreignKeys;
+	}
+
+	/**
+	 * Creates a table column.
+	 * @param array column metadata
+	 * @return TDbColumnSchema normalized column metadata
+	 */
+	protected function createColumn($column)
+	{
+		$c=new TSqliteColumnSchema;
+		$c->name=$column['name'];
+		$c->rawName=$this->quoteColumnName($c->name);
+		$c->allowNull=!$column['notnull'];
+		$c->isPrimaryKey=$column['pk']!=0;
+		$c->isForeignKey=false;
+		$c->init(strtolower($column['type']),$column['dflt_value']);
+		return $c;
+	}
+}
-- 
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