* @link http://www.pradosoft.com/
* @copyright Copyright © 2005-2007 PradoSoft
* @license http://www.pradosoft.com/license/
* @version $Id$
* @package System.Data.ActiveRecord.Relations
*/
/**
* Loads base active record relations class.
*/
Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordRelation');
/**
* Implements the M-N (many to many) relationship via association table.
* Consider the entity relationship between Articles and Categories
* via the association table Article_Category.
*
* +---------+ +------------------+ +----------+
* | Article | * -----> * | Article_Category | * <----- * | Category |
* +---------+ +------------------+ +----------+
*
* Where one article may have 0 or more categories and each category may have 0
* or more articles. We may model Article-Category object relationship
* as active record as follows.
*
* class ArticleRecord
* {
* const TABLE='Article';
* public $article_id;
*
* public $Categories=array(); //foreign object collection.
*
* protected static $RELATIONS = array
* (
* 'Categories' => array(self::HAS_MANY, 'CategoryRecord', 'Article_Category')
* );
*
* public static function finder($className=__CLASS__)
* {
* return parent::finder($className);
* }
* }
* class CategoryRecord
* {
* const TABLE='Category';
* public $category_id;
*
* public $Articles=array();
*
* protected static $RELATIONS = array
* (
* 'Articles' => array(self::HAS_MANY, 'ArticleRecord', 'Article_Category')
* );
*
* public static function finder($className=__CLASS__)
* {
* return parent::finder($className);
* }
* }
*
*
* The static $RELATIONS property of ArticleRecord defines that the
* property $Categories has many CategoryRecords. Similar, the
* static $RELATIONS property of CategoryRecord defines many ArticleRecords.
*
* The articles with categories list may be fetched as follows.
*
* $articles = TeamRecord::finder()->withCategories()->findAll();
*
* The method with_xxx() (where xxx is the relationship property
* name, in this case, Categories) fetchs the corresponding CategoryRecords using
* a second query (not by using a join). The with_xxx() accepts the same
* arguments as other finder methods of TActiveRecord.
*
* @author Wei Zhuo
* @version $Id$
* @package System.Data.ActiveRecord.Relations
* @since 3.1
*/
class TActiveRecordHasManyAssociation extends TActiveRecordRelation
{
private $_association;
private $_sourceTable;
private $_foreignTable;
/**
* Get the foreign key index values from the results and make calls to the
* database to find the corresponding foreign objects using association table.
* @param array original results.
*/
protected function collectForeignObjects(&$results)
{
$association = $this->getAssociationTable();
$sourceKeys = $this->findForeignKeys($association, $this->getSourceRecord());
$properties = array_values($sourceKeys);
$indexValues = $this->getIndexValues($properties, $results);
$fkObject = $this->getContext()->getForeignRecordFinder();
$foreignKeys = $this->findForeignKeys($association, $fkObject);
$this->fetchForeignObjects($results, $foreignKeys,$indexValues,$sourceKeys);
}
/**
* @return TDbTableInfo association table information.
*/
protected function getAssociationTable()
{
if($this->_association===null)
{
$gateway = $this->getSourceRecord()->getRecordGateway();
$conn = $this->getSourceRecord()->getDbConnection();
$table = $this->getContext()->getAssociationTable();
$this->_association = $gateway->getTableInfo($conn, $table);
}
return $this->_association;
}
/**
* @return TDbTableInfo source table information.
*/
protected function getSourceTable()
{
if($this->_sourceTable===null)
{
$gateway = $this->getSourceRecord()->getRecordGateway();
$this->_sourceTable = $gateway->getRecordTableInfo($this->getSourceRecord());
}
return $this->_sourceTable;
}
/**
* @return TDbTableInfo foreign table information.
*/
protected function getForeignTable()
{
if($this->_foreignTable===null)
{
$gateway = $this->getSourceRecord()->getRecordGateway();
$fkObject = $this->getContext()->getForeignRecordFinder();
$this->_foreignTable = $gateway->getRecordTableInfo($fkObject);
}
return $this->_foreignTable;
}
/**
* @return TDbCommandBuilder
*/
protected function getCommandBuilder()
{
return $this->getSourceRecord()->getRecordGateway()->getCommand($this->getSourceRecord());
}
/**
* Fetches the foreign objects using TActiveRecord::findAllByIndex()
* @param array field names
* @param array foreign key index values.
*/
protected function fetchForeignObjects(&$results,$foreignKeys,$indexValues,$sourceKeys)
{
$criteria = $this->getContext()->getCriteria();
$finder = $this->getContext()->getForeignRecordFinder();
$registry = $finder->getRecordManager()->getObjectStateRegistry();
$type = get_class($finder);
$command = $this->createCommand($criteria, $foreignKeys,$indexValues,$sourceKeys);
$srcProps = array_keys($sourceKeys);
$collections=array();
foreach($command->query() as $row)
{
$hash = $this->getObjectHash($row, $srcProps);
foreach($srcProps as $column)
unset($row[$column]);
$obj = new $type($row);
$collections[$hash][] = $obj;
$registry->registerClean($obj);
}
$this->setResultCollection($results, $collections, array_values($sourceKeys));
}
/**
* @param TSqlCriteria
* @param TTableInfo association table info
* @param array field names
* @param array field values
*/
public function createCommand($criteria, $foreignKeys,$indexValues,$sourceKeys)
{
$innerJoin = $this->getAssociationJoin($foreignKeys,$indexValues,$sourceKeys);
$fkTable = $this->getForeignTable()->getTableFullName();
$srcColumns = $this->getSourceColumns($sourceKeys);
if(($where=$criteria->getCondition())===null)
$where='1=1';
$sql = "SELECT {$fkTable}.*, {$srcColumns} FROM {$fkTable} {$innerJoin} WHERE {$where}";
$parameters = $criteria->getParameters()->toArray();
$ordering = $criteria->getOrdersBy();
$limit = $criteria->getLimit();
$offset = $criteria->getOffset();
$builder = $this->getCommandBuilder()->getBuilder();
$command = $builder->applyCriterias($sql,$parameters,$ordering,$limit,$offset);
$this->getCommandBuilder()->onCreateCommand($command, $criteria);
return $command;
}
/**
* @param array source table column names.
* @return string comma separated source column names.
*/
protected function getSourceColumns($sourceKeys)
{
$columns=array();
$table = $this->getAssociationTable();
$tableName = $table->getTableFullName();
foreach($sourceKeys as $name=>$fkName)
$columns[] = $tableName.'.'.$table->getColumn($name)->getColumnName();
return implode(', ', $columns);
}
/**
* SQL inner join for M-N relationship via association table.
* @param array foreign table column key names.
* @param array source table index values.
* @param array source table column names.
* @return string inner join condition for M-N relationship via association table.
*/
protected function getAssociationJoin($foreignKeys,$indexValues,$sourceKeys)
{
$refInfo= $this->getAssociationTable();
$fkInfo = $this->getForeignTable();
$refTable = $refInfo->getTableFullName();
$fkTable = $fkInfo->getTableFullName();
$joins = array();
foreach($foreignKeys as $ref=>$fk)
{
$refField = $refInfo->getColumn($ref)->getColumnName();
$fkField = $fkInfo->getColumn($fk)->getColumnName();
$joins[] = "{$fkTable}.{$fkField} = {$refTable}.{$refField}";
}
$joinCondition = implode(' AND ', $joins);
$index = $this->getCommandBuilder()->getIndexKeyCondition($refInfo,array_keys($sourceKeys), $indexValues);
return "INNER JOIN {$refTable} ON ({$joinCondition}) AND {$index}";
}
}
?>