12 files changed, 1571 insertions, 164 deletions
diff --git a/framework/Data/ActiveRecord/TActiveRecord.php b/framework/Data/ActiveRecord/TActiveRecord.php
index 109ae9a6..70fd7b23 100644
--- a/framework/Data/ActiveRecord/TActiveRecord.php
+++ b/framework/Data/ActiveRecord/TActiveRecord.php
@@ -250,10 +250,7 @@ abstract class TActiveRecord extends TComponent
 		if(is_string($criteria))
 		{
 			if(!is_array($parameters) && func_num_args() > 1)
-			{
-				$parameters = func_get_args();
-				array_shift($parameters);
-			}
+				$parameters = array_slice(func_get_args(),1);
 			$criteria=new TActiveRecordCriteria($criteria,$parameters);
 		}
 		$gateway = $this->getRecordManager()->getRecordGateway();
@@ -309,10 +306,7 @@ abstract class TActiveRecord extends TComponent
 		if(is_string($criteria))
 		{
 			if(!is_array($parameters) && func_num_args() > 1)
-			{
-				$parameters = func_get_args();
-				array_shift($parameters);
-			}
+				$parameters = array_slice(func_get_args(),1);
 			$criteria=new TActiveRecordCriteria($criteria,$parameters);
 		}
 		$gateway = $this->getRecordManager()->getRecordGateway();
@@ -332,10 +326,7 @@ abstract class TActiveRecord extends TComponent
 		if(is_string($criteria))
 		{
 			if(!is_array($parameters) && func_num_args() > 1)
-			{
-				$parameters = func_get_args();
-				array_shift($parameters);
-			}
+				$parameters = array_slice(func_get_args(),1);
 			$criteria=new TActiveRecordCriteria($criteria,$parameters);
 		}
 		$gateway = $this->getRecordManager()->getRecordGateway();
@@ -407,10 +398,7 @@ abstract class TActiveRecord extends TComponent
 	public function findBySql($sql,$parameters=array())
 	{
 		if(!is_array($parameters) && func_num_args() > 1)
-		{
-			$parameters = func_get_args();
-			array_shift($parameters);
-		}
+			$parameters = array_slice(func_get_args(),1);
 		$gateway = $this->getRecordManager()->getRecordGateway();
 		$data = $gateway->findRecordsBySql($this,$sql,$parameters);
 		$results = array();
@@ -430,11 +418,8 @@ abstract class TActiveRecord extends TComponent
 	{
 		if(is_string($criteria))
 		{
-			if(!is_array($parameters) && func_num_args() > 1)
-			{
-				$parameters = func_get_args();
-				array_shift($parameters);
-			}
+			if(!is_array($parameters) && func_num_args() > 1)
+				$parameters = array_slice(func_get_args(),1);
 			$criteria=new TActiveRecordCriteria($criteria,$parameters);
 		}
 		$gateway = $this->getRecordManager()->getRecordGateway();
diff --git a/framework/Data/ActiveRecord/TActiveRecordCriteria.php b/framework/Data/ActiveRecord/TActiveRecordCriteria.php
index 134632e8..cc4da7c8 100644
--- a/framework/Data/ActiveRecord/TActiveRecordCriteria.php
+++ b/framework/Data/ActiveRecord/TActiveRecordCriteria.php
@@ -10,6 +10,8 @@
  * @package System.Data.ActiveRecord
  */
 
+Prado::using('System.Data.DataGateway.TSqlCriteria');
+
 /**
  * Search criteria for Active Record.
  *
@@ -30,125 +32,8 @@
  * @package System.Data.ActiveRecord
  * @since 3.1
  */
-class TActiveRecordCriteria extends TComponent
+class TActiveRecordCriteria extends TSqlCriteria
 {
-	private $_condition;
-	private $_parameters;
-	private $_ordersBy;
-	private $_limit;
-	private $_offset;
-
-	/**
-	 * Creates a new criteria with given condition;
-	 * @param string sql string after the WHERE stanza
-	 * @param mixed named or indexed parameters, accepts as multiple arguments.
-	 */
-	public function __construct($condition=null,$parameters=array())
-	{
-		if(!is_array($parameters) && func_num_args() > 2)
-		{
-			$parameters = func_get_args();
-			array_shift($parameters);
-		}
-		$this->setCondition($condition);
-		$this->_parameters=new TAttributeCollection((array)$parameters);
-		$this->_ordersBy=new TAttributeCollection;
-	}
-
-	/**
-	 * @return TAttributeCollection list of named parameters and values.
-	 */
-	public function getParameters()
-	{
-		return $this->_parameters;
-	}
-
-	/**
-	 * @param ArrayAccess named parameters.
-	 */
-	public function setParameters($value)
-	{
-		if(!(is_array($value) || $value instanceof ArrayAccess))
-			throw new TException('value must be array or ArrayAccess');
-		$this->_parameters->copyFrom($value);
-	}
-
-	/**
-	 * @return boolean true if the parameter index are string base, false otherwise.
-	 */
-	public function getIsNamedParameters()
-	{
-		foreach($this->getParameters() as $k=>$v)
-			return is_string($k);
-	}
-
-	/**
-	 * @return TAttributeCollection ordering clause.
-	 */
-	public function getOrdersBy()
-	{
-		return $this->_ordersBy;
-	}
-
-	/**
-	 * @param ArrayAccess ordering clause.
-	 */
-	public function setOrdersBy($value)
-	{
-		if(!(is_array($value) || $value instanceof ArrayAccess))
-			throw new TException('value must be array or ArrayAccess');
-		$this->_ordersBy->copyFrom($value);
-	}
-
-	/**
-	 * @return string search conditions.
-	 */
-	public function getCondition()
-	{
-		return $this->_condition;
-	}
-
-	/**
-	 * Sets the search conditions to be placed after the WHERE clause in the SQL.
-	 * @param string search conditions.
-	 */
-	public function setCondition($value)
-	{
-		$this->_condition=$value;
-	}
-
-	/**
-	 * @return int maximum number of records to return.
-	 */
-	public function getLimit()
-	{
-		return $this->_limit;
-	}
-
-	/**
-	 * @param int maximum number of records to return.
-	 */
-	public function setLimit($value)
-	{
-		$this->_limit=$value;
-	}
-
-	/**
-	 * @return int record offset.
-	 */
-	public function getOffset()
-	{
-		return $this->_offset;
-	}
-
-	/**
-	 * @param int record offset.
-	 */
-	public function setOffset($value)
-	{
-		$this->_offset=$value;
-	}
-
 	/**
 	 * This method is invoked before the object is deleted from the database.
 	 * The method raises 'OnDelete' event.
@@ -172,31 +57,6 @@ class TActiveRecordCriteria extends TComponent
 	{
 		$this->raiseEvent('OnSelect', $this, $param);
 	}
-
-	/**
-	 * @return string string representation of the criteria. Useful for debugging.
-	 */
-	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->_limit !==null)
-			$str .= ', '.$this->_limit;
-		if($this->_offset !== null)
-			$str .= ', '.$this->_offset;
-		return $str;
-	}
 }
 
 ?>
 \ No newline at end of file
diff --git a/framework/Data/Common/Mysql/TMysqlMetaData.php b/framework/Data/Common/Mysql/TMysqlMetaData.php
new file mode 100644
index 00000000..ee3bd2e0
--- /dev/null
+++ b/framework/Data/Common/Mysql/TMysqlMetaData.php
@@ -0,0 +1,251 @@
+<?php
+
+/**
+ * Load the base TDbMetaData class.
+ */
+Prado::using('System.Data.Common.TDbMetaData');
+Prado::using('System.Data.Common.Mysql.TMysqlTableInfo');
+
+class TMysqlMetaData extends TDbMetaData
+{
+	/**
+	 * Get the column definitions for given table.
+	 * @param string table name.
+	 * @return TMysqlTableInfo table information.
+	 */
+	protected function createTableInfo($table)
+	{
+		$this->getDbConnection()->setActive(true);
+		$sql = "SHOW FULL FIELDS FROM {$table}";
+		$command = $this->getDbConnection()->createCommand($sql);
+		$tableInfo = $this->createNewTableInfo($table);
+		$index=0;
+		foreach($command->query() as $col)
+		{
+			$col['index'] = $index++;
+			$this->processColumn($tableInfo,$col);
+		}
+		return $tableInfo;
+	}
+
+	/**
+	 * @param TMysqlTableInfo table information.
+	 * @param array column information.
+	 */
+	protected function processColumn($tableInfo, $col)
+	{
+		$columnId = $col['Field'];
+
+		$info['ColumnName'] = "`$columnId`"; //quote the column names!
+		$info['ColumnIndex'] = $col['index'];
+		if($col['Null']!=='NO')
+			$info['AllowNull'] = true;
+		if(is_int(strpos(strtolower($col['Extra']), 'auto_increment')))
+			$info['AutoIncrement']=true;
+		if($col['Default']!=="")
+			$info['DefaultValue'] = $col['Default'];
+
+		if($col['Key']==='PRI' || in_array($columnId, $tableInfo->getPrimaryKeys()))
+			$info['IsPrimaryKey'] = true;
+		if($this->isForeignKeyColumn($columnId, $tableInfo))
+			$info['IsForeignKey'] = true;
+		if(in_array($columnId, $tableInfo->getUniqueKeys()))
+			$info['IsUnique'] = true;
+
+		$info['DbType'] = $col['Type'];
+		$match=array();
+		//find SET/ENUM values, column size, precision, and scale
+		if(preg_match('/\((.*)\)/', $col['Type'], $match))
+		{
+			$info['DbType']= preg_replace('/\(.*\)/', '', $col['Type']);
+
+			//find SET/ENUM values
+			if($this->isEnumSetType($info['DbType']))
+				$info['DbTypeValues'] = preg_split('/\s*,\s*|\s+/', preg_replace('/\'|"/', '', $match[1]));
+
+			//find column size, precision and scale
+			$pscale = array();
+			if(preg_match('/(\d+)(?:,(\d+))?+/', $match[1], $pscale))
+			{
+				if($this->isPrecisionType($info['DbType']))
+				{
+					$info['NumericPrecision'] = intval($pscale[1]);
+					if(count($pscale) > 2)
+						$info['NumericScale'] = intval($pscale[2]);
+				}
+				else
+					$info['ColumnSize'] = intval($pscale[1]);
+			}
+		}
+
+		$tableInfo->Columns[$columnId] = new TMysqlTableColumn($info);
+	}
+
+	/**
+	 * @return boolean true if column type if "numeric", "interval" or begins with "time".
+	 */
+	protected function isPrecisionType($type)
+	{
+		$type = strtolower(trim($type));
+		return $type==='decimal' || $type==='dec'
+				|| $type==='float' || $type==='double'
+				|| $type==='double precision' || $type==='real';
+	}
+
+	/**
+	 * @return boolean true if column type if "enum" or "set".
+	 */
+	protected function isEnumSetType($type)
+	{
+		$type = strtolower(trim($type));
+		return $type==='set' || $type==='enum';
+	}
+
+
+	/**
+	 * @param string table name, may be quoted with back-ticks and may contain database name.
+	 * @return array tuple ($schema,$table), $schema may be null.
+	 * @throws TDbException when table name contains invalid identifier bytes.
+	 */
+	protected function getSchemaTableName($table)
+	{
+		//remove the back ticks and separate out the "database.table"
+		$result = explode('.', str_replace('`', '', $table));
+		foreach($result as $name)
+		{
+			if(!$this->isValidIdentifier($name))
+			{
+				$ref = 'http://dev.mysql.com/doc/refman/5.0/en/identifiers.html';
+				throw new TDbException('dbcommon_invalid_identifier_name', $table, $ref);
+			}
+		}
+		return count($result) > 1 ? $result : array(null, $result[0]);
+	}
+
+	/**
+	 * http://dev.mysql.com/doc/refman/5.0/en/identifiers.html
+	 * @param unknown_type $name
+	 */
+	protected function isValidIdentifier($name)
+	{
+		return !preg_match('#/|\\|.|\x00|\xFF#', $name);
+	}
+
+	/**
+	 * @param string table schema name
+	 * @param string table name.
+	 * @return TMysqlTableInfo
+	 */
+	protected function createNewTableInfo($table)
+	{
+		list($schemaName,$tableName) = $this->getSchemaTableName($table);
+		$info['SchemaName'] = $schemaName;
+		$info['TableName'] = $tableName;
+		$info['IsView'] = $this->getIsView($schemaName,$tableName);
+		list($primary, $foreign, $unique) = $this->getConstraintKeys($schemaName, $tableName);
+		return new TMysqlTableInfo($info,$primary,$foreign, $unique);
+	}
+
+	/**
+	 * @param string database name, null to use default connection database.
+	 * @param string table or view name.
+	 * @return boolean true if is view, false otherwise.
+	 * @throws TDbException if table or view does not exist.
+	 */
+	protected function getIsView($schemaName,$tableName)
+	{
+		if($schemaName!==null)
+			$sql = "SHOW FULL TABLES FROM `{$schemaName}` LIKE :table";
+		else
+			$sql = 'SHOW FULL TABLES LIKE :table';
+
+		$command = $this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table', $tableName);
+		try
+		{
+			return count($result = $command->queryRow()) > 0 && $result['Table_type']==='VIEW';
+		}
+		catch(TDbException $e)
+		{
+			$table = $schemaName===null?$tableName:$schemaName.'.'.$tableName;
+			throw new TDbException('dbcommon_invalid_table_name',$table,$e->getMessage());
+		}
+	}
+
+	/**
+	 * Gets the primary, foreign key, and unique column details for the given table.
+	 * @param string schema name
+	 * @param string table name.
+	 * @return array tuple ($primary, $foreign, $unique)
+	 */
+	protected function getConstraintKeys($schemaName, $tableName)
+	{
+		$table = $schemaName===null ? "`{$tableName}`" : "`{$schemaName}`.`{$tableName}`";
+		$sql = "SHOW INDEX FROM {$table}";
+		$command = $this->getDbConnection()->createCommand($sql);
+		$primary = array();
+		$foreign = $this->getForeignConstraints($schemaName,$tableName);
+		$unique = array();
+		foreach($command->query() as $row)
+		{
+			if($row['Key_name']==='PRIMARY')
+				$primary[] = $row['Column_name'];
+			else if(intval($row['Non_unique'])===0)
+				$unique[] = $row['Column_name'];
+		}
+		return array($primary,$foreign,$unique);
+	}
+
+	/**
+	 * Gets foreign relationship constraint keys and table name
+	 * @param string database name
+	 * @param string table name
+	 * @return array foreign relationship table name and keys.
+	 */
+	protected function getForeignConstraints($schemaName, $tableName)
+	{
+		$andSchema = $schemaName !== null ? 'AND TABLE_SCHEMA = :schema' : '';
+		$sql = <<<EOD
+			SELECT
+				CONSTRAINT_NAME as con,
+				COLUMN_NAME as col,
+				REFERENCED_TABLE_SCHEMA as fkschema,
+				REFERENCED_TABLE_NAME as fktable,
+				REFERENCED_COLUMN_NAME as fkcol
+			FROM
+				 `INFORMATION_SCHEMA`.`KEY_COLUMN_USAGE`
+			WHERE
+				REFERENCED_TABLE_NAME IS NOT NULL
+				AND TABLE_NAME = :table
+				$andSchema
+EOD;
+		$command = $this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table', $tableName);
+		if($schemaName!==null)
+			$command->bindValue(':schema', $schemaName);
+		$fkeys=array();
+		foreach($command->query() as $col)
+		{
+			$fkeys[$col['con']]['keys'][$col['col']] = $col['fkcol'];
+			$fkeys[$col['con']]['table'] = "`{$col['fkschema']}`.`{$col['fktable']}`";
+		}
+		return array_values($fkeys);
+	}
+
+	/**
+	 * @param string column name.
+	 * @param TPgsqlTableInfo table information.
+	 * @return boolean true if column is a foreign key.
+	 */
+	protected function isForeignKeyColumn($columnId, $tableInfo)
+	{
+		foreach($tableInfo->getForeignKeys() as $fk)
+		{
+			if(in_array($columnId, array_keys($fk['keys'])))
+				return true;
+		}
+		return false;
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/Mysql/TMysqlTableColumn.php b/framework/Data/Common/Mysql/TMysqlTableColumn.php
new file mode 100644
index 00000000..0f013acd
--- /dev/null
+++ b/framework/Data/Common/Mysql/TMysqlTableColumn.php
@@ -0,0 +1,69 @@
+<?php
+/**
+ * TMysqlTableColumn class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common.Mysql
+ */
+
+/**
+ * Load common TDbTableCommon class.
+ */
+Prado::using('System.Data.Common.TDbTableColumn');
+
+/**
+ * Describes the column metadata of the schema for a Mysql database table.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Common.Mysql
+ * @since 3.1
+ */
+class TMysqlTableColumn extends TDbTableColumn
+{
+	/**
+	 * @return boolean true if column will auto-increment when the column value is inserted as null.
+	 */
+	public function getAutoIncrement()
+	{
+		return $this->getInfo('AutoIncrement', false);
+	}
+
+	/**
+	 * @return boolean true if auto increment is true.
+	 */
+	public function getHasSequence()
+	{
+		return $this->getAutoIncrement();
+	}
+
+	public function getDbTypeValues()
+	{
+		return $this->getInfo('DbTypeValues');
+	}
+
+	/**
+	 * Overrides parent implementation, returns PHP type from the db type.
+	 * @return boolean derived PHP primitive type from the column db type.
+	 */
+	public function getPHPType()
+	{
+		switch(strtolower($this->getDbType()))
+		{
+			case 'bit': case 'bit varying': case 'real': case 'serial': case 'int': case 'integer':
+				return 'integer';
+			case 'boolean':
+				return 'boolean';
+			case 'bigint': case 'bigserial': case 'double precision': case 'money': case 'numeric':
+				return 'float';
+			default:
+				return 'string';
+		}
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/Mysql/TMysqlTableInfo.php b/framework/Data/Common/Mysql/TMysqlTableInfo.php
new file mode 100644
index 00000000..e8585730
--- /dev/null
+++ b/framework/Data/Common/Mysql/TMysqlTableInfo.php
@@ -0,0 +1,46 @@
+<?php
+/**
+ * TMysqlTableInfo class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common.Mysql
+ */
+
+/**
+ * Loads the base TDbTableInfo class and TMysqlTableColumn class.
+ */
+Prado::using('System.Data.Common.TDbTableInfo');
+Prado::using('System.Data.Common.Mysql.TMysqlTableColumn');
+
+/**
+ * TMysqlTableInfo class provides additional table information for MySQL database.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Common.Mysql
+ * @since 3.1
+ */
+class TMysqlTableInfo extends TDbTableInfo
+{
+	/**
+	 * @return string name of the schema this column belongs to.
+	 */
+	public function getSchemaName()
+	{
+		return $this->getInfo('SchemaName');
+	}
+
+	/**
+	 * @return string full name of the table, database dependent.
+	 */
+	public function getTableFullName()
+	{
+		return '`'.$this->getSchemaName().'`.`'.$this->getTableName().'`';
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/Pgsql/TPgsqlMetaData.php b/framework/Data/Common/Pgsql/TPgsqlMetaData.php
new file mode 100644
index 00000000..b789192f
--- /dev/null
+++ b/framework/Data/Common/Pgsql/TPgsqlMetaData.php
@@ -0,0 +1,329 @@
+<?php
+/**
+ * TPgsqlMetaData class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common.Pgsql
+ */
+
+/**
+ * Load the base TDbMetaData class.
+ */
+Prado::using('System.Data.Common.TDbMetaData');
+Prado::using('System.Data.Common.Pgsql.TPgsqlTableInfo');
+
+/**
+ * TPgsqlMetaData loads PostgreSQL database table and column information.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Commom.Pgsql
+ * @since 3.1
+ */
+class TPgsqlMetaData extends TDbMetaData
+{
+	private $_defaultSchema = 'public';
+
+	/**
+	 * @param string default schema.
+	 */
+	public function setDefaultSchema($schema)
+	{
+		$this->_defaultSchema=$schema;
+	}
+
+	/**
+	 * @return string default schema.
+	 */
+	public function getDefaultSchema()
+	{
+		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)
+	{
+		if(count($parts= explode('.', $table)) > 1)
+			return array($parts[0], $parts[1]);
+		else
+			return array($this->getDefaultSchema(),$parts[0]);
+	}
+
+	/**
+	 * Get the column definitions for given table.
+	 * @param string table name.
+	 * @return TPgsqlTableInfo table information.
+	 */
+	protected function createTableInfo($table)
+	{
+		list($schemaName,$tableName) = $this->getSchemaTableName($table);
+
+		// This query is made much more complex by the addition of the 'attisserial' field.
+		// The subquery to get that field checks to see if there is an internally dependent
+		// sequence on the field.
+		$sql =
+<<<EOD
+		SELECT
+			a.attname,
+			pg_catalog.format_type(a.atttypid, a.atttypmod) as type,
+			a.atttypmod,
+			a.attnotnull, a.atthasdef, adef.adsrc,
+			(
+				SELECT 1 FROM pg_catalog.pg_depend pd, pg_catalog.pg_class pc
+				WHERE pd.objid=pc.oid
+				AND pd.classid=pc.tableoid
+				AND pd.refclassid=pc.tableoid
+				AND pd.refobjid=a.attrelid
+				AND pd.refobjsubid=a.attnum
+				AND pd.deptype='i'
+				AND pc.relkind='S'
+			) IS NOT NULL AS attisserial
+
+		FROM
+			pg_catalog.pg_attribute a LEFT JOIN pg_catalog.pg_attrdef adef
+			ON a.attrelid=adef.adrelid
+			AND a.attnum=adef.adnum
+			LEFT JOIN pg_catalog.pg_type t ON a.atttypid=t.oid
+		WHERE
+			a.attrelid = (SELECT oid FROM pg_catalog.pg_class WHERE relname=:table
+				AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace WHERE
+				nspname = :schema))
+			AND a.attnum > 0 AND NOT a.attisdropped
+		ORDER BY a.attnum
+EOD;
+		$this->getDbConnection()->setActive(true);
+		$command = $this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table', $tableName);
+		$command->bindValue(':schema', $schemaName);
+		$tableInfo = $this->createNewTableInfo($schemaName, $tableName);
+		$index=0;
+		foreach($command->query() as $col)
+		{
+			$col['index'] = $index++;
+			$this->processColumn($tableInfo, $col);
+		}
+		return $tableInfo;
+	}
+
+	/**
+	 * @param string table schema name
+	 * @param string table name.
+	 * @return TPgsqlTableInfo
+	 */
+	protected function createNewTableInfo($schemaName,$tableName)
+	{
+		$info['SchemaName'] = $schemaName;
+		$info['TableName'] = $tableName;
+		if($this->getIsView($schemaName,$tableName))
+			$info['IsView'] = true;
+		list($primary, $foreign, $unique) = $this->getConstraintKeys($schemaName, $tableName);
+		return new TPgsqlTableInfo($info,$primary,$foreign, $unique);
+	}
+
+	/**
+	 * @param string table schema name
+	 * @param string table name.
+	 * @return boolean true if the table is a view.
+	 */
+	protected function getIsView($schemaName,$tableName)
+	{
+		$sql =
+<<<EOD
+		SELECT count(c.relname) FROM pg_catalog.pg_class c
+		LEFT JOIN pg_catalog.pg_namespace n ON (n.oid = c.relnamespace)
+		WHERE (n.nspname=:schema) AND (c.relkind = 'v'::"char") AND c.relname = :table
+EOD;
+		$this->getDbConnection()->setActive(true);
+		$command = $this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':schema',$schemaName);
+		$command->bindValue(':table', $tableName);
+		return intval($command->queryScalar()) === 1;
+	}
+
+	/**
+	 * @param TPgsqlTableInfo table information.
+	 * @param array column information.
+	 */
+	protected function processColumn($tableInfo, $col)
+	{
+		$columnId = $col['attname']; //use column name as column Id
+
+		$info['ColumnName'] = '"'.$columnId.'"'; //quote the column names!
+		$info['ColumnIndex'] = $col['index'];
+		if(!$col['attnotnull'])
+			$info['AllowNull'] = true;
+		if(in_array($columnId, $tableInfo->getPrimaryKeys()))
+			$info['IsPrimaryKey'] = true;
+		if($this->isForeignKeyColumn($columnId, $tableInfo))
+			$info['IsForeignKey'] = true;
+		if(in_array($columnId, $tableInfo->getUniqueKeys()))
+			$info['IsUnique'] = true;
+
+		if($col['atttypmod'] > 0)
+			$info['ColumnSize'] =  $col['atttypmod'] - 4;
+		if($col['atthasdef'])
+			$info['DefaultValue'] = $col['adsrc'];
+		if($col['attisserial'] || substr($col['adsrc'],0,8) === 'nextval(')
+		{
+			if(($sequence = $this->getSequenceName($tableInfo, $col['adsrc']))!==null)
+			{
+				$info['SequenceName'] = $sequence;
+				unset($info['DefaultValue']);
+			}
+		}
+		$matches = array();
+		if(preg_match('/\((\d+)(?:,(\d+))?+\)/', $col['type'], $matches))
+		{
+			$info['DbType'] = preg_replace('/\(\d+(?:,\d+)?\)/','',$col['type']);
+			if($this->isPrecisionType($info['DbType']))
+			{
+				$info['NumericPrecision'] = intval($matches[1]);
+				if(count($matches) > 2)
+					$info['NumericScale'] = intval($matches[2]);
+			}
+			else
+				$info['ColumnSize'] = intval($matches[1]);
+		}
+		else
+			$info['DbType'] = $col['type'];
+
+		$tableInfo->Columns[$columnId] = new TPgsqlTableColumn($info);
+	}
+
+	/**
+	 * @return string serial name if found, null otherwise.
+	 */
+	protected function getSequenceName($tableInfo,$src)
+	{
+		$matches = array();
+		if(preg_match('/nextval\([^\']*\'([^\']+)\'[^\)]*\)/i',$src,$matches))
+		{
+			if(is_int(strpos($matches[1], '.')))
+				return $matches[1];
+			else
+				return $tableInfo->getSchemaName().'.'.$matches[1];
+		}
+	}
+
+	/**
+	 * @return boolean true if column type if "numeric", "interval" or begins with "time".
+	 */
+	protected function isPrecisionType($type)
+	{
+		$type = strtolower(trim($type));
+		return $type==='numeric' || $type==='interval' || strpos($type, 'time')===0;
+	}
+
+	/**
+	 * Gets the primary, foreign key, and unique column details for the given table.
+	 * @param string schema name
+	 * @param string table name.
+	 * @return array tuple ($primary, $foreign, $unique)
+	 */
+	protected function getConstraintKeys($schemaName, $tableName)
+	{
+		$sql = 'SELECT
+				pg_catalog.pg_get_constraintdef(pc.oid, true) AS consrc,
+				pc.contype
+			FROM
+				pg_catalog.pg_constraint pc
+			WHERE
+				pc.conrelid = (SELECT oid FROM pg_catalog.pg_class WHERE relname=:table
+					AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace
+					WHERE nspname=:schema))
+		';
+		$this->getDbConnection()->setActive(true);
+		$command = $this->getDbConnection()->createCommand($sql);
+		$command->bindValue(':table', $tableName);
+		$command->bindValue(':schema', $schemaName);
+		$primary = array();
+		$foreign = array();
+		$unique = array();
+		foreach($command->query() as $row)
+		{
+			switch($row['contype'])
+			{
+				case 'p':
+					$primary = $this->getPrimaryKeys($row['consrc']);
+					break;
+				case 'f':
+					if(($fkey = $this->getForeignKeys($row['consrc']))!==null)
+						$foreign[] = $fkey;
+					break;
+				case 'u':
+					if(($ukey = $this->getUniqueKey($row['consrc']))!==null)
+						$unique[] = $ukey;
+					break;
+			}
+		}
+		return array($primary,$foreign,$unique);
+	}
+
+	/**
+	 * Gets the primary key field names
+	 * @param string pgsql primary key definition
+	 * @return array primary key field names.
+	 */
+	protected function getPrimaryKeys($src)
+	{
+		$matches = array();
+		if(preg_match('/PRIMARY\s+KEY\s+\(([^\)]+)\)/i', $src, $matches))
+			return preg_split('/,\s+/',$matches[1]);
+		return array();
+	}
+
+	/**
+	 * @param string pgsql unique constraint definition
+	 * @return string column id if found, null otherwise.
+	 */
+	protected function getUniqueKey($src)
+	{
+		$matches=array();
+		if(preg_match('/UNIQUE\s+\(([^\)]+)\)/i', $src, $matches))
+			return $matches[1];
+	}
+
+	/**
+	 * Gets foreign relationship constraint keys and table name
+	 * @param string pgsql foreign key definition
+	 * @return array foreign relationship table name and keys, null otherwise
+	 */
+	protected function getForeignKeys($src)
+	{
+		$matches = array();
+		$brackets = '\(([^\)]+)\)';
+		$find = "/FOREIGN\s+KEY\s+{$brackets}\s+REFERENCES\s+([^\(]+){$brackets}/i";
+		if(preg_match($find, $src, $matches))
+		{
+			$keys = preg_split('/,\s+/', $matches[1]);
+			$fkeys = array();
+			foreach(preg_split('/,\s+/', $matches[3]) as $i => $fkey)
+				$fkeys[$keys[$i]] = $fkey;
+			return array('table' => $matches[2], 'keys' => $fkeys);
+		}
+	}
+
+	/**
+	 * @param string column name.
+	 * @param TPgsqlTableInfo table information.
+	 * @return boolean true if column is a foreign key.
+	 */
+	protected function isForeignKeyColumn($columnId, $tableInfo)
+	{
+		foreach($tableInfo->getForeignKeys() as $fk)
+		{
+			if(in_array($columnId, array_keys($fk['keys'])))
+				return true;
+		}
+		return false;
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/Pgsql/TPgsqlTableColumn.php b/framework/Data/Common/Pgsql/TPgsqlTableColumn.php
new file mode 100644
index 00000000..66053a63
--- /dev/null
+++ b/framework/Data/Common/Pgsql/TPgsqlTableColumn.php
@@ -0,0 +1,48 @@
+<?php
+/**
+ * TPgsqlTableColumn class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common.Pgsql
+ */
+
+/**
+ * Load common TDbTableCommon class.
+ */
+Prado::using('System.Data.Common.TDbTableColumn');
+
+/**
+ * Describes the column metadata of the schema for a PostgreSQL database table.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Common.Pgsql
+ * @since 3.1
+ */
+class TPgsqlTableColumn extends TDbTableColumn
+{
+	/**
+	 * Overrides parent implementation, returns PHP type from the db type.
+	 * @return boolean derived PHP primitive type from the column db type.
+	 */
+	public function getPHPType()
+	{
+		switch(strtolower($this->getDbType()))
+		{
+			case 'bit': case 'bit varying': case 'real': case 'serial': case 'int': case 'integer':
+				return 'integer';
+			case 'boolean':
+				return 'boolean';
+			case 'bigint': case 'bigserial': case 'double precision': case 'money': case 'numeric':
+				return 'float';
+			default:
+				return 'string';
+		}
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/Pgsql/TPgsqlTableInfo.php b/framework/Data/Common/Pgsql/TPgsqlTableInfo.php
new file mode 100644
index 00000000..88a56635
--- /dev/null
+++ b/framework/Data/Common/Pgsql/TPgsqlTableInfo.php
@@ -0,0 +1,46 @@
+<?php
+/**
+ * TPgsqlTableInfo class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common.Pgsql
+ */
+
+/**
+ * Loads the base TDbTableInfo class and TPgsqlTableColumn class.
+ */
+Prado::using('System.Data.Common.TDbTableInfo');
+Prado::using('System.Data.Common.Pgsql.TPgsqlTableColumn');
+
+/**
+ * TPgsqlTableInfo class provides additional table information for PostgreSQL database.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Common.Pgsql
+ * @since 3.1
+ */
+class TPgsqlTableInfo extends TDbTableInfo
+{
+	/**
+	 * @return string name of the schema this column belongs to.
+	 */
+	public function getSchemaName()
+	{
+		return $this->getInfo('SchemaName');
+	}
+
+	/**
+	 * @return string full name of the table, database dependent.
+	 */
+	public function getTableFullName()
+	{
+		return $this->getSchemaName().'.'.$this->getTableName();
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/TDbCommandBuilder.php b/framework/Data/Common/TDbCommandBuilder.php
new file mode 100644
index 00000000..5238a045
--- /dev/null
+++ b/framework/Data/Common/TDbCommandBuilder.php
@@ -0,0 +1,320 @@
+<?php
+/**
+ * TDbCommandBuilder class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common
+ */
+
+/**
+ * TDbCommandBuilder provides basic methods to create query commands for tables
+ * giving by {@link setTableInfo TableInfo} the property.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Common
+ * @since 3.1
+ */
+class TDbCommandBuilder extends TComponent
+{
+	private $_connection;
+	private $_tableInfo;
+
+	/**
+	 * @param TDbConnection database connection.
+	 * @param TDbTableInfo table information.
+	 */
+	public function __construct($connection=null, $tableInfo=null)
+	{
+		$this->setDbConnection($connection);
+		$this->setTableInfo($tableInfo);
+	}
+
+	/**
+	 * @return TDbConnection database connection.
+	 */
+	public function getDbConnection()
+	{
+		return $this->_connection;
+	}
+
+	/**
+	 * @param TDbConnection database connection.
+	 */
+	public function setDbConnection($value)
+	{
+		$this->_connection=$value;
+	}
+
+	/**
+	 * @param TDbTableInfo table information.
+	 */
+	public function setTableInfo($value)
+	{
+		$this->_tableInfo=$value;
+	}
+
+	/**
+	 * @param TDbTableInfo table information.
+	 */
+	public function getTableInfo()
+	{
+		return $this->_tableInfo;
+	}
+
+	/**
+	 * Alters the sql to apply $limit and $offset. Default implementation is applicable
+	 * for PostgreSQL, MySQL and SQLite.
+	 * @param string SQL query string.
+	 * @param integer maximum number of rows, -1 to ignore limit.
+	 * @param integer row offset, -1 to ignore offset.
+	 * @return string SQL with limit and offset.
+	 */
+	public function applyLimitOffset($sql, $limit=-1, $offset=-1)
+	{
+		$limit = $limit!==null ? intval($limit) : -1;
+		$offset = $offset!==null ? intval($offset) : -1;
+		$limitStr = $limit >= 0 ? ' LIMIT '.$limit : '';
+		$offsetStr = $offset >= 0 ? ' OFFSET '.$offset : '';
+		return $sql.$limitStr.$offsetStr;
+	}
+
+	/**
+	 * @param string SQL string without existing ordering.
+	 * @param array pairs of column names as key and direction as value.
+	 * @return string modified SQL applied with ORDER BY.
+	 */
+	public function applyOrdering($sql, $ordering)
+	{
+		$orders=array();
+		foreach($ordering as $name=>$direction)
+		{
+			$direction = strtolower($direction) == 'desc' ? 'DESC' : 'ASC';
+			$column = $this->getTableInfo()->getColumn($name)->getColumnName();
+			$orders[] = $column.' '.$direction;
+		}
+		if(count($orders) > 0)
+			$sql .= ' ORDER BY '.implode(', ', $orders);
+		return $sql;
+	}
+
+	/**
+	 * Computes the SQL condition for search a set of column using regular expression
+	 * to match a string of keywords. The implementation should only uses columns
+	 * that permit regular expression matching. This method should be implemented in
+	 * database specific command builder classes.
+	 * @param array list of column id for potential search condition.
+	 * @param string string of keywords
+	 * @return string SQL condition for regular expression matching on a set of columns.
+	 */
+	//abstract public function createRegExpSearch($columnIds, $keywords);
+
+	/**
+	 * Appends the $where condition to the string "SELECT * FROM tableName WHERE ".
+	 * The tableName is obtained from the {@link setTableInfo TableInfo} property.
+	 * @param string query condition
+	 * @param array condition parameters.
+	 * @return TDbCommand query command.
+	 */
+	public function createFindCommand($where, $parameters=array(), $ordering=array(), $limit=-1, $offset=-1)
+	{
+		$table = $this->getTableInfo()->getTableFullName();
+		$sql = "SELECT * FROM {$table} WHERE {$where}";
+		if(count($ordering) > 0)
+			$sql = $this->applyOrdering($sql, $ordering);
+		if($limit>=0 || $offset>=0)
+			$sql = $this->applyLimitOffset($sql, $limit, $offset);
+		$command = $this->createCommand($sql);
+		$this->bindArrayValues($command, $parameters);
+		return $command;
+	}
+
+	/**
+	 * Creates a count(*) command for the table described in {@link setTableInfo TableInfo}.
+	 * @param string count condition.
+	 * @param array binding parameters.
+	 * @return TDbCommand count command.
+	 */
+	public function createCountCommand($where='true', $parameters=array(),$ordering=array(), $limit=-1, $offset=-1)
+	{
+		$table = $this->getTableInfo()->getTableFullName();
+		$sql = "SELECT COUNT(*) FROM {$table} WHERE {$where}";
+		if(count($ordering) > 0)
+			$sql = $this->applyOrdering($sql, $ordering);
+		if($limit>=0 || $offset>=0)
+			$sql = $this->applyLimitOffset($sql, $limit, $offset);
+		$command = $this->createCommand($sql);
+		$this->bindArrayValues($command, $parameters);
+		return $command;
+	}
+
+	/**
+	 * Creates a delete command for the table described in {@link setTableInfo TableInfo}.
+	 * The conditions for delete is given by the $where argument and the parameters
+	 * for the condition is given by $parameters.
+	 * @param string delete condition.
+	 * @param array delete parameters.
+	 * @return TDbCommand delete command.
+	 */
+	public function createDeleteCommand($where,$parameters=array())
+	{
+		$table = $this->getTableInfo()->getTableFullName();
+		$command = $this->createCommand("DELETE FROM {$table} WHERE {$where}");
+		$this->bindArrayValues($command, $parameters);
+		return $command;
+	}
+
+	/**
+	 * Creates an insert command for the table described in {@link setTableInfo TableInfo} for the given data.
+	 * Each array key in the $data array must correspond to the column name of the table
+	 * (if a column allows to be null, it may be omitted) to be inserted with
+	 * the corresponding array value.
+	 * @param array name-value pairs of new data to be inserted.
+	 * @return TDbCommand insert command
+	 */
+	public function createInsertCommand($data)
+	{
+		$table = $this->getTableInfo()->getTableFullName();
+		list($fields, $bindings) = $this->getInsertFieldBindings($data);
+		$command = $this->createCommand("INSERT INTO {$table}({$fields}) VALUES ($bindings)");
+		$this->bindColumnValues($command, $data);
+		return $command;
+	}
+
+	/**
+	 * Creates an update command for the table described in {@link setTableInfo TableInfo} for the given data.
+	 * Each array key in the $data array must correspond to the column name to be updated with the corresponding array value.
+	 * @param array name-value pairs of data to be updated.
+	 * @param string update condition.
+	 * @param array update parameters.
+	 * @return TDbCommand update command.
+	 */
+	public function createUpdateCommand($data, $where, $parameters=array())
+	{
+		$table = $this->getTableInfo()->getTableFullName();
+		if($this->hasIntegerKey($parameters))
+			$fields = implode(', ', $this->getColumnBindings($data, true));
+		else
+			$fields = implode(', ', $this->getColumnBindings($data));
+		$command = $this->createCommand("UPDATE {$table} SET {$fields} WHERE {$where}");
+		$this->bindArrayValues($command, array_merge($data, $parameters));
+		return $command;
+	}
+
+	/**
+	 * Returns a list of insert field name and a list of binding names.
+	 * @param object array or object to be inserted.
+	 * @return array tuple ($fields, $bindings)
+	 */
+	protected function getInsertFieldBindings($values)
+	{
+		$fields = array(); $bindings=array();
+		foreach(array_keys($values) as $name)
+		{
+			$fields[] = $this->getTableInfo()->getColumn($name)->getColumnName();
+			$bindings[] = ':'.$name;
+		}
+		return array(implode(', ',$fields), implode(', ', $bindings));
+	}
+
+	/**
+	 * Create a name-value or position-value if $position=true binding strings.
+	 * @param array data for binding.
+	 * @param boolean true to bind as position values.
+	 * @return string update column names with corresponding binding substrings.
+	 */
+	protected function getColumnBindings($values, $position=false)
+	{
+		$bindings=array();
+		foreach(array_keys($values) as $name)
+		{
+			$column = $this->getTableInfo()->getColumn($name)->getColumnName();
+			$bindings[] = $position ? $column.' = ?' : $column.' = :'.$name;
+		}
+		return $bindings;
+	}
+
+	/**
+	 * @param string SQL query string.
+	 * @return TDbCommand corresponding database command.
+	 */
+	public function createCommand($sql)
+	{
+		$this->getDbConnection()->setActive(true);
+		return $this->getDbConnection()->createCommand($sql);
+	}
+
+	/**
+	 * Bind the name-value pairs of $values where the array keys correspond to column names.
+	 * @param TDbCommand database command.
+	 * @param array name-value pairs.
+	 */
+	public function bindColumnValues($command, $values)
+	{
+		foreach($values as $name=>$value)
+		{
+			$column = $this->getTableInfo()->getColumn($name);
+			if($value === null && $column->getAllowNull())
+				$command->bindValue(':'.$name, null, PDO::PARAM_NULL);
+			else
+				$command->bindValue(':'.$name, $value, $column->getPdoType());
+		}
+	}
+
+	/**
+	 * @param TDbCommand database command
+	 * @param array values for binding.
+	 */
+	public function bindArrayValues($command, $values)
+	{
+		if($this->hasIntegerKey($values))
+		{
+			$values = array_values($values);
+			for($i = 0, $max=count($values); $i<$max; $i++)
+				$command->bindValue($i+1, $values[$i], $this->getPdoType($value));
+		}
+		else
+		{
+			foreach($values as $name=>$value)
+			{
+				$prop = $name[0]===':' ? $name : ':'.$name;
+				$command->bindValue($prop, $value, $this->getPdoType($value));
+			}
+		}
+	}
+
+	/**
+	 * @param mixed PHP value
+	 * @return integer PDO parameter types.
+	 */
+	protected function getPdoType($value)
+	{
+		switch(gettype($value))
+		{
+			case 'boolean': return PDO::PARAM_BOOL;
+			case 'integer': return PDO::PARAM_INT;
+			case 'string' : return PDO::PARAM_STR;
+			case 'NULL'   : return PDO::PARAM_NULL;
+		}
+	}
+
+	/**
+	 * @param array
+	 * @return boolean true if any array key is an integer.
+	 */
+	protected function hasIntegerKey($array)
+	{
+		foreach($array as $k=>$v)
+		{
+			if(gettype($k)==='integer')
+				return true;
+		}
+		return false;
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/TDbMetaData.php b/framework/Data/Common/TDbMetaData.php
new file mode 100644
index 00000000..477e2805
--- /dev/null
+++ b/framework/Data/Common/TDbMetaData.php
@@ -0,0 +1,104 @@
+<?php
+/**
+ * TDbMetaData class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common
+ */
+
+/**
+ * TDbMetaData is the base class for retrieving metadata information, such as
+ * table and columns information, from a database connection.
+ *
+ * Use the {@link getTableInfo} method to retrieve a table information.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Common
+ * @since 3.1
+ */
+abstract class TDbMetaData extends TComponent
+{
+	private $_tableInfoCache=array();
+	private $_connection;
+
+	/**
+	 * @param TDbConnection database connection.
+	 */
+	public function __construct($conn)
+	{
+		$this->_connection=$conn;
+	}
+
+	/**
+	 * @return TDbConnection database connection.
+	 */
+	public function getDbConnection()
+	{
+		return $this->_connection;
+	}
+
+	/**
+	 * Obtain database specific TDbMetaData class using the driver name of the database connection.
+	 * @param TDbConnection database connection.
+	 * @return TDbMetaData database specific TDbMetaData.
+	 */
+	public static function getMetaData($conn)
+	{
+		$conn->setActive(true); //must be connected before retrieving driver name
+		$driver = $conn->getDriverName();
+		switch(strtolower($driver))
+		{
+			case 'pgsql':
+				Prado::using('System.Data.Common.Pgsql.TPgsqlMetaData');
+				return new TPgsqlMetaData($conn);
+			case 'mysqli':
+			case 'mysql':
+				Prado::using('System.Data.Common.Mysql.TMysqlMetaData');
+				return new TMysqlMetaData($conn);
+			case 'sqlite': //sqlite 3
+			case 'sqlite2': //sqlite 2
+				Prado::using('System.Data.Common.Sqlite.TSqliteMetaData');
+				return new TSqliteMetaData($conn);
+			case 'ibm':
+				Prado::using('System.Data.Common.IbmDb2.TIbmDb2MetaData');
+				return new TIbmDb2MetaData($conn);
+			default:
+				throw new TDbException('ar_invalid_database_driver',$driver);
+		}
+	}
+
+	/**
+	 * Obtains table meta data information for the current connection and given table name.
+	 * @param string table or view name
+	 * @return TDbTableInfo table information.
+	 */
+	public function getTableInfo($tableName)
+	{
+		if(!isset($this->_tableInfoCache[$tableName]))
+			$this->_tableInfoCache[$tableName] = $this->createTableInfo($tableName);
+		return $this->_tableInfoCache[$tableName];
+	}
+
+	/**
+	 * Creates a command builder for a given table name.
+	 * @param string table name.
+	 * @return TDbCommandBuilder command builder instance for the given table.
+	 */
+	public function createCommandBuilder($tableName)
+	{
+		return $this->getTableInfo($tableName)->createCommandBuilder($this->getDbConnection());
+	}
+
+	/**
+	 * This method should be implemented by decendent classes.
+	 * @return TDbTableInfo driver dependent create builder.
+	 */
+	abstract protected function createTableInfo($tableName);
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/TDbTableColumn.php b/framework/Data/Common/TDbTableColumn.php
new file mode 100644
index 00000000..4d9bd8a0
--- /dev/null
+++ b/framework/Data/Common/TDbTableColumn.php
@@ -0,0 +1,182 @@
+<?php
+/**
+ * TDbTableColumn class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common
+ */
+
+/**
+ * TDbTableColumn class describes the column meta data of the schema for a database table.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Common
+ * @since 3.1
+ */
+class TDbTableColumn extends TComponent
+{
+	const UNDEFINED_VALUE= INF; //use infinity for undefined value
+
+	private $_info=array();
+
+	/**
+	 * Sets the table column meta data.
+	 * @param array table column information.
+	 */
+	public function __construct($columnInfo)
+	{
+		$this->_info=$columnInfo;
+	}
+
+	/**
+	 * @param string information array key name
+	 * @param mixed default value if information array value is null
+	 * @return mixed information array value.
+	 */
+	protected function getInfo($name,$default=null)
+	{
+		return isset($this->_info[$name]) ? $this->_info[$name] : $default;
+	}
+
+	/**
+	 * @param string information array key name
+	 * @param mixed new information array value.
+	 */
+	protected function setInfo($name,$value)
+	{
+		$this->_info[$name]=$value;
+	}
+
+	/**
+	 * Returns the derived PHP primitive type from the db type. Default returns 'string'.
+	 * @return string derived PHP primitive type from the column db type.
+	 */
+	public function getPHPType()
+	{
+		return 'string';
+	}
+
+	/**
+	 * @param integer PDO bind param/value types.
+	 */
+	public function getPdoType()
+	{
+		switch($this->getPHPType())
+		{
+			case 'boolean': return PDO::PARAM_BOOL;
+			case 'integer': return PDO::PARAM_INT;
+			case 'string' : return PDO::PARAM_STR;
+		}
+	}
+
+	/**
+	 * @return string name of the column in the table (identifier quoted).
+	 */
+	public function getColumnName()
+	{
+		return $this->getInfo('ColumnName');
+	}
+
+	/**
+	 * @return string size of the column.
+	 */
+	public function getColumnSize()
+	{
+		return $this->getInfo('ColumnSize');
+	}
+
+	/**
+	 * @return integer zero-based ordinal position of the column in the table.
+	 */
+	public function getColumnIndex()
+	{
+		return $this->getInfo('ColumnIndex');
+	}
+
+	/**
+	 * @return string column type.
+	 */
+	public function getDbType()
+	{
+		return $this->getInfo('DbType');
+	}
+
+	/**
+	 * @return boolean specifies whether value Null is allowed, default is false.
+	 */
+	public function getAllowNull()
+	{
+		return $this->getInfo('AllowNull',false);
+	}
+
+	/**
+	 * @return mixed default column value if column value was null.
+	 */
+	public function getDefaultValue()
+	{
+		return $this->getInfo('DefaultValue', self::UNDEFINED_VALUE);
+	}
+
+	/**
+	 * @return string precision of the column data, if the data is numeric.
+	 */
+	public function getNumericPrecision()
+	{
+		return $this->getInfo('NumericPrecision');
+	}
+
+	/**
+	 * @return string scale of the column data, if the data is numeric.
+	 */
+	public function getNumericScale()
+	{
+		return $this->getInfo('NumericScale');
+	}
+
+	/**
+	 * @return boolean whether this column is a primary key for the table, default is false.
+	 */
+	public function getIsPrimaryKey()
+	{
+		return $this->getInfo('IsPrimaryKey',false);
+	}
+
+	/**
+	 * @return boolean whether this column is a foreign key, default is false.
+	 */
+	public function getIsForeignKey()
+	{
+		return $this->getInfo('IsForeignKey',false);
+	}
+
+	/**
+	 * @return boolean whether a unique constraint applies to this column, default is false.
+	 */
+	public function getIsUnique()
+	{
+		return $this->getInfo('IsUnique', false);
+	}
+
+	/**
+	 * @param string sequence name, only applicable if column is a sequence
+	 */
+	public function getSequenceName()
+	{
+		return $this->getInfo('SequenceName');
+	}
+
+	/**
+	 * @return boolean whether the column is a sequence.
+	 */
+	public function hasSequence()
+	{
+		return $this->getSequenceName()!==null;
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/Common/TDbTableInfo.php b/framework/Data/Common/TDbTableInfo.php
new file mode 100644
index 00000000..9b7f4392
--- /dev/null
+++ b/framework/Data/Common/TDbTableInfo.php
@@ -0,0 +1,167 @@
+<?php
+/**
+ * TDbTableInfo class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Data.Common
+ */
+
+/**
+ * TDbTableInfo class describes the meta data of a database table.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id$
+ * @package System.Data.Common
+ * @since 3.1
+ */
+class TDbTableInfo extends TComponent
+{
+	private $_info=array();
+
+	private $_primaryKeys;
+	private $_foreignKeys;
+	private $_uniqueKeys;
+
+	private $_columns;
+
+	private $_lowercase;
+
+	/**
+	 * Sets the database table meta data information.
+	 * @param array table column information.
+	 */
+	public function __construct($tableInfo,$primary=array(),$foreign=array(), $unique=array())
+	{
+		$this->_info=$tableInfo;
+		$this->_primaryKeys=$primary;
+		$this->_foreignKeys=$foreign;
+		$this->_uniqueKeys=$unique;
+		$this->_columns=new TMap;
+	}
+
+	/**
+	 * @param TDbConnection database connection.
+	 * @return TDbCommandBuilder new command builder
+	 */
+	public function createCommandBuilder($connection)
+	{
+		Prado::using('System.Data.Common.TDbCommandBuilder');
+		return new TDbCommandBuilder($connection,$this);
+	}
+
+	/**
+	 * @param string information array key name
+	 * @param mixed default value if information array value is null
+	 * @return mixed information array value.
+	 */
+	protected function getInfo($name,$default=null)
+	{
+		return isset($this->_info[$name]) ? $this->_info[$name] : $default;
+	}
+
+	/**
+	 * @param string information array key name
+	 * @param mixed new information array value.
+	 */
+	protected function setInfo($name,$value)
+	{
+		$this->_info[$name]=$value;
+	}
+
+	/**
+	 * @return string name of the table this column belongs to.
+	 */
+	public function getTableName()
+	{
+		return $this->getInfo('TableName');
+	}
+
+	/**
+	 * @return string full name of the table, database dependent.
+	 */
+	public function getTableFullName()
+	{
+		return $this->getTableName();
+	}
+
+	/**
+	 * @return boolean whether the table is a view, default is false.
+	 */
+	public function getIsView()
+	{
+		return $this->getInfo('IsView',false);
+	}
+
+	/**
+	 * @return TMap TDbTableColumn column meta data.
+	 */
+	public function getColumns()
+	{
+		return $this->_columns;
+	}
+
+	/**
+	 * @param string column id
+	 * @return TDbTableColumn column information.
+	 */
+	public function getColumn($name)
+	{
+		return $this->_columns->itemAt($name);
+	}
+
+	/**
+	 * @param array list of column Id, empty to get all columns.
+	 * @return array table column names (identifier quoted)
+	 */
+	public function getColumnNames()
+	{
+		$names=array();
+		foreach($this->getColumns() as $column)
+			$names[] = $column->getColumnName();
+		return $names;
+	}
+
+	/**
+	 * @return string[] names of primary key columns.
+	 */
+	public function getPrimaryKeys()
+	{
+		return $this->_primaryKeys;
+	}
+
+	/**
+	 * @return array tuples of foreign table and column name.
+	 */
+	public function getForeignKeys()
+	{
+		return $this->_foreignKeys;
+	}
+
+	/**
+	 * @return array unique column ids.
+	 */
+	public function getUniqueKeys()
+	{
+		return $this->_uniqueKeys;
+	}
+
+	/**
+	 * @return array lowercased column key names mapped to normal column ids.
+	 */
+	public function getLowerCaseColumnNames()
+	{
+		if($this->_lowercase===null)
+		{
+			$this->_lowercase=array();
+			foreach($this->getColumns()->getKeys() as $key)
+				$this->_lowercase[strtolower($key)] = $key;
+		}
+		return $this->_lowercase;
+	}
+}
+
+?>
+\ No newline at end of file