/yii/framework/db/ar/CActiveRecord.php

<?php
/**
 * CActiveRecord class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 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 3317 2011-06-24 20:38:49Z qiang.xue $
 * @package system.db.ar
 * @since 1.0
 *
 * @property array $attributes
 */
abstract class CActiveRecord extends CModel
{
	const BELONGS_TO='CBelongsToRelation';
	const HAS_ONE='CHasOneRelation';
	const HAS_MANY='CHasManyRelation';
	const MANY_MANY='CManyManyRelation';
	const STAT='CStatRelation';

	/**
	 * @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)
	private $_pk;								// old primary key value
	private $_alias='t';						// the table alias being used for query


	/**
	 * Constructor.
	 * @param string $scenario scenario name. See {@link CModel::scenario} for more details about this parameter.
	 */
	public function __construct($scenario='insert')
	{
		if($scenario===null) // internally used by populateRecord() and model()
			return;

		$this->setScenario($scenario);
		$this->setIsNewRecord(true);
		$this->_attributes=$this->getMetaData()->attributeDefaults;

		$this->init();

		$this->attachBehaviors($this->behaviors());
		$this->afterConstruct();
	}

	/**
	 * Initializes this model.
	 * This method is invoked when an AR instance is newly created and has
	 * its {@link scenario} set.
	 * You may override this method to provide code that is needed to initialize the model (e.g. setting
	 * initial property values.)
	 * @since 1.0.8
	 */
	public function init()
	{
	}

	/**
	 * Sets the parameters about query caching.
	 * This is a shortcut method to {@link CDbConnection::cache()}.
	 * It changes the query caching parameter of the {@link dbConnection} instance.
	 * @param integer $duration the number of seconds that query results may remain valid in cache.
	 * If this is 0, the caching will be disabled.
	 * @param CCacheDependency $dependency the dependency that will be used when saving the query results into cache.
	 * @param integer $queryCount number of SQL queries that need to be cached after calling this method. Defaults to 1,
	 * meaning that the next SQL query will be cached.
	 * @return CActiveRecord the active record instance itself.
	 * @since 1.1.7
	 */
	public function cache($duration, $dependency=null, $queryCount=1)
	{
		$this->getDbConnection()->cache($duration, $dependency, $queryCount);
		return $this;
	}

	/**
	 * PHP sleep magic method.
	 * This method ensures that the model meta data reference is set to null.
	 * @return array
	 */
	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 $name property name
	 * @return mixed property value
	 * @see getAttribute
	 */
	public function __get($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 $name property name
	 * @param mixed $value property value
	 */
	public function __set($name,$value)
	{
		if($this->setAttribute($name,$value)===false)
		{
			if(isset($this->getMetaData()->relations[$name]))
				$this->_related[$name]=$value;
			else
				parent::__set($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 $name the property name or the event name
	 * @return boolean whether the property value is null
	 * @since 1.0.1
	 */
	public function __isset($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 $name the property name or the event name
	 * @since 1.0.1
	 */
	public function __unset($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 $name the method name
	 * @param array $parameters method parameters
	 * @return mixed the method return value
	 * @since 1.0.5
	 */
	public function __call($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 $name the relation name (see {@link relations})
	 * @param boolean $refresh whether to reload the related objects from database. Defaults to false.
	 * @param array $params additional parameters that customize the query conditions as specified in the relation declaration.
	 * This parameter has been available since version 1.0.5.
	 * @return mixed the related object(s).
	 * @throws CDbException if the relation is not specified in {@link relations}.
	 * @since 1.0.2
	 */
	public function getRelated($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 CDbException(Yii::t('yii','{class} does not have relation "{name}".',
				array('{class}'=>get_class($this), '{name}'=>$name)));

		Yii::trace('lazy loading '.get_class($this).'.'.$name,'system.db.ar.CActiveRecord');
		$relation=$md->relations[$name];
		if($this->getIsNewRecord() && !$refresh && ($relation instanceof CHasOneRelation || $relation instanceof CHasManyRelation))
			return $relation instanceof CHasOneRelation ? null : array();

		if($params!==array()) // dynamic query
		{
			$exists=isset($this->_related[$name]) || array_key_exists($name,$this->_related);
			if($exists)
				$save=$this->_related[$name];
			$r=array($name=>$params);
		}
		else
			$r=$name;
		unset($this->_related[$name]);

		$finder=new CActiveFinder($this,$r);
		$finder->lazyFind($this);

		if(!isset($this->_related[$name]))
		{
			if($relation instanceof CHasManyRelation)
				$this->_related[$name]=array();
			else if($relation instanceof CStatRelation)
				$this->_related[$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 $name the relation name
	 * @return boolean a value indicating whether the named related object(s) has been loaded.
	 * @since 1.0.3
	 */
	public function hasRelated($name)
	{
		return isset($this->_related[$name]) || array_key_exists($name,$this->_related);
	}

	/**
	 * Returns the query criteria associated with this model.
	 * @param boolean $createIfNull whether to create a criteria instance if it does not exist. Defaults to true.
	 * @return CDbCriteria the query criteria that is associated with this model.
	 * This criteria is mainly used by {@link scopes named scope} feature to accumulate
	 * different criteria specifications.
	 * @since 1.0.5
	 */
	public function getDbCriteria($createIfNull=true)
	{
		if($this->_c===null)
		{
			if(($c=$this->defaultScope())!==array() || $createIfNull)
				$this->_c=new CDbCriteria($c);
		}
		return $this->_c;
	}

	/**
	 * Sets the query criteria for the current model.
	 * @param CDbCriteria $criteria the query criteria
	 * @since 1.1.3
	 */
	public function setDbCriteria($criteria)
	{
		$this->_c=$criteria;
	}

	/**
	 * Returns the default named scope that should be implicitly applied to all queries for this model.
	 * Note, default scope only applies to SELECT queries. It is ignored for INSERT, UPDATE and DELETE queries.
	 * 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();
	}

	/**
	 * Resets all scopes and criterias applied including default scope.
	 *
	 * @return CActiveRecord
	 * @since 1.1.2
	 */
	public function resetScope()
	{
		$this->_c=new CDbCriteria();
		return $this;
	}

	/**
	 * 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 $className active record class name.
	 * @return CActiveRecord active record model instance.
	 */
	public static function model($className=__CLASS__)
	{
		if(isset(self::$_models[$className]))
			return self::$_models[$className];
		else
		{
			$model=self::$_models[$className]=new $className(null);
			$model->_md=new CActiveRecordMetaData($model);
			$model->attachBehaviors($model->behaviors());
			return $model;
		}
	}

	/**
	 * Returns the meta-data for this AR
	 * @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;
	}

	/**
	 * Refreshes the meta data for this AR class.
	 * By calling this method, this AR class will regenerate the meta data needed.
	 * This is useful if the table schema has been changed and you want to use the latest
	 * available table schema. Make sure you have called {@link CDbSchema::refresh}
	 * before you call this method. Otherwise, old table schema data will still be used.
	 * @since 1.0.8
	 */
	public function refreshMetaData()
	{
		$finder=self::model(get_class($this));
		$finder->_md=new CActiveRecordMetaData($finder);
		if($this!==$finder)
			$this->_md=$finder->_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>
	 *
	 * Besides the above relation types, a special relation called STAT is also supported
	 * that can be used to perform statistical query (or aggregational query).
	 * It retrieves the aggregational information about the related objects, such as the number
	 * of comments for each post, the average rating for each product, etc.
	 *
	 * Each kind of related objects is defined in this method as an array with the following elements:
	 * <pre>
	 * 'varName'=>array('relationType', 'className', 'foreign_key', ...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 'foreign_key' states the foreign key that relates the two kinds of active record.
	 * Note, for composite foreign keys, they must be listed together, separated by commas;
	 * and for foreign keys used in MANY_MANY relation, the joining table must be declared as well
	 * (e.g. 'join_table(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(relationName.name) AS name_count).</li>
	 * <li>'condition': string, the WHERE clause. Defaults to empty. Note, column references need to
	 *   be disambiguated with prefix 'relationName.' (e.g. relationName.age&gt;20)</li>
	 * <li>'order': string, the ORDER BY clause. Defaults to empty. Note, column references need to
	 *   be disambiguated with prefix 'relationName.' (e.g. relationName.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>
	 * <li>'index': the name of the column whose values should be used as keys
	 *   of the array that stores related objects. This option is only available to
	 *   HAS_MANY and MANY_MANY relations. This option has been available since version 1.0.7.</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 'relationName.' (e.g. relationName.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 'relationName.' (e.g. relationName.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>
	 * <li>'through': name of the model's relation that will be used as a bridge when getting related data. Can be set only for HAS_ONE and HAS_MANY. This option has been available since version 1.1.7.</li>
	 * </ul>
	 *
	 * Below is an example declaring related objects for 'Post' active record class:
	 * <pre>
	 * return array(
	 *     'author'=>array(self::BELONGS_TO, 'User', 'author_id'),
	 *     'comments'=>array(self::HAS_MANY, 'Comment', 'post_id', 'with'=>'author', 'order'=>'create_time DESC'),
	 *     'tags'=>array(self::MANY_MANY, 'Tag', 'post_tag(post_id, tag_id)', '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'=>'create_time 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 text label for the specified attribute.
	 * This method overrides the parent implementation by supporting
	 * returning the label defined in relational object.
	 * In particular, if the attribute name is in the form of "post.author.name",
	 * then this method will derive the label from the "author" relation's "name" attribute.
	 * @param string $attribute the attribute name
	 * @return string the attribute label
	 * @see generateAttributeLabel
	 * @since 1.1.4
	 */
	public function getAttributeLabel($attribute)
	{
		$labels=$this->attributeLabels();
		if(isset($labels[$attribute]))
			return $labels[$attribute];
		else if(strpos($attribute,'.')!==false)
		{
			$segs=explode('.',$attribute);
			$name=array_pop($segs);
			$model=$this;
			foreach($segs as $seg)
			{
				$relations=$model->getMetaData()->relations;
				if(isset($relations[$seg]))
					$model=CActiveRecord::model($relations[$seg]->className);
				else
					break;
			}
			return $model->getAttributeLabel($name);
		}
		else
			return $this->generateAttributeLabel($attribute);
	}

	/**
	 * 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.
	 */
	public function getDbConnection()
	{
		if(self::$db!==null)
			return self::$db;
		else
		{
			self::$db=Yii::app()->getDb();
			if(self::$db instanceof CDbConnection)
				return self::$db;
			else
				throw new CDbException(Yii::t('yii','Active Record requires a "db" CDbConnection application component.'));
		}
	}

	/**
	 * Returns the named relation declared for this AR class.
	 * @param string $name the relation name
	 * @return CActiveRelation the named relation declared for this AR class. Null if the relation does not exist.
	 */
	public function getActiveRelation($name)
	{
		return isset($this->getMetaData()->relations[$name]) ? $this->getMetaData()->relations[$name] : null;
	}

	/**
	 * Returns the metadata of the table that this AR belongs to
	 * @return CDbTableSchema the metadata of the table that this AR belongs to
	 */
	public function getTableSchema()
	{
		return $this->getMetaData()->tableSchema;
	}

	/**
	 * Returns the command builder used by this AR.
	 * @return CDbCommandBuilder the command builder used by this AR
	 */
	public function getCommandBuilder()
	{
		return $this->getDbConnection()->getSchema()->getCommandBuilder();
	}

	/**
	 * Checks whether this AR has the named attribute
	 * @param string $name attribute name
	 * @return boolean whether this AR has the named attribute (table column).
	 */
	public function hasAttribute($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 $name the attribute name
	 * @return mixed the attribute value. Null if the attribute is not set or does not exist.
	 * @see hasAttribute
	 */
	public function getAttribute($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 $name the attribute name
	 * @param mixed $value the attribute value.
	 * @return boolean whether the attribute exists and the assignment is conducted successfully
	 * @see hasAttribute
	 */
	public function setAttribute($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;
	}

	/**
	 * Do not call this method. This method is used internally by {@link CActiveFinder} to populate
	 * related objects. This method adds a related object to this record.
	 * @param string $name attribute name
	 * @param mixed $record the related record
	 * @param mixed $index the index value in the related object collection.
	 * If true, it means using zero-based integer index.
	 * If false, it means a HAS_ONE or BELONGS_TO object and no index is needed.
	 */
	public function addRelatedRecord($name,$record,$index)
	{
		if($index!==false)
		{
			if(!isset($this->_related[$name]))
				$this->_related[$name]=array();
			if($record instanceof CActiveRecord)
			{
				if($index===true)
					$this->_related[$name][]=$record;
				else
					$this->_related[$name][$index]=$record;
			}
		}
		else if(!isset($this->_related[$name]))
			$this->_related[$name]=$record;
	}

	/**
	 * Returns all column attribute values.
	 * Note, related objects are not returned.
	 * @param mixed $names names of attributes whose value needs to be returned.
	 * If this is true (default), then all attribute values will be returned, including
	 * those that are not loaded from DB (null will be returned for those attributes).
	 * If this is null, all attributes except those that are not loaded from DB will be returned.
	 * @return array attribute values indexed by attribute names.
	 */
	public function getAttributes($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 $name)
			{
				if(property_exists($this,$name))
					$attrs[$name]=$this->$name;
				else
					$attrs[$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 $runValidation whether to perform validation before saving the record.
	 * If the validation fails, the record will not be saved to database.
	 * @param array $attributes list of attributes that need to be saved. Defaults to null,
	 * meaning all attributes that are loaded from DB will be saved.
	 * @return boolean whether the saving succeeds
	 */
	public function save($runValidation=true,$attributes=null)
	{
		if(!$runValidation || $this->validate($attributes))
			return $this->getIsNewRecord() ? $this->insert($attributes) : $this->update($attributes);
		else
			return false;
	}

	/**
	 * Returns if the current record is new.
	 * @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;
	}

	/**
	 * Sets if the record is new.
	 * @param boolean $value whether the record is new and should be inserted when calling {@link save}.
	 * @see getIsNewRecord
	 */
	public function setIsNewRecord($value)
	{
		$this->_new=$value;
	}

	/**
	 * This event is raised before the record is saved.
	 * By setting {@link CModelEvent::isValid} to be false, the normal {@link save()} process will be stopped.
	 * @param CModelEvent $event the event parameter
	 * @since 1.0.2
	 */
	public function onBeforeSave($event)
	{
		$this->raiseEvent('onBeforeSave',$event);
	}

	/**
	 * This event is raised after the record is saved.
	 * @param CEvent $event the event parameter
	 * @since 1.0.2
	 */
	public function onAfterSave($event)
	{
		$this->raiseEvent('onAfterSave',$event);
	}

	/**
	 * This event is raised before the record is deleted.
	 * By setting {@link CModelEvent::isValid} to be false, the normal {@link delete()} process will be stopped.
	 * @param CModelEvent $event the event parameter
	 * @since 1.0.2
	 */
	public function onBeforeDelete($event)
	{
		$this->raiseEvent('onBeforeDelete',$event);
	}

	/**
	 * This event is raised after the record is deleted.
	 * @param CEvent $event the event parameter
	 * @since 1.0.2
	 */
	public function onAfterDelete($event)
	{
		$this->raiseEvent('onAfterDelete',$event);
	}

	/**
	 * This event is raised before an AR finder performs a find call.
	 * In this event, the {@link CModelEvent::criteria} property contains the query criteria
	 * passed as parameters to those find methods. If you want to access
	 * the query criteria specified in scopes, please use {@link getDbCriteria()}.
	 * You can modify either criteria to customize them based on needs.
	 * @param CModelEvent $event the event parameter
	 * @see beforeFind
	 * @since 1.0.9
	 */
	public function onBeforeFind($event)
	{
		$this->raiseEvent('onBeforeFind',$event);
	}

	/**
	 * This event is raised after the record is instantiated by a find method.
	 * @param CEvent $event the event parameter
	 * @since 1.0.2
	 */
	public function onAfterFind($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()
	{
		if($this->hasEventHandler('onBeforeSave'))
		{
			$event=new CModelEvent($this);
			$this->onBeforeSave($event);
			return $event->isValid;
		}
		else
			return true;
	}

	/**
	 * This method is invoked after saving a record successfully.
	 * 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()
	{
		if($this->hasEventHandler('onAfterSave'))
			$this->onAfterSave(new CEvent($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()
	{
		if($this->hasEventHandler('onBeforeDelete'))
		{
			$event=new CModelEvent($this);
			$this->onBeforeDelete($event);
			return $event->isValid;
		}
		else
			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()
	{
		if($this->hasEventHandler('onAfterDelete'))
			$this->onAfterDelete(new CEvent($this));
	}

	/**
	 * This method is invoked before an AR finder executes a find call.
	 * The find calls include {@link find}, {@link findAll}, {@link findByPk},
	 * {@link findAllByPk}, {@link findByAttributes} and {@link findAllByAttributes}.
	 * The default implementation raises the {@link onBeforeFind} event.
	 * If you override this method, make sure you call the parent implementation
	 * so that the event is raised properly.
	 *
	 * Starting from version 1.1.5, this method may be called with a hidden {@link CDbCriteria}
	 * parameter which represents the current query criteria as passed to a find method of AR.
	 *
	 * @since 1.0.9
	 */
	protected function beforeFind()
	{
		if($this->hasEventHandler('onBeforeFind'))
		{
			$event=new CModelEvent($this);
			// for backward compatibility
			$event->criteria=func_num_args()>0 ? func_get_arg(0) : null;
			$this->onBeforeFind($event);
		}
	}

	/**
	 * 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()
	{
		if($this->hasEventHandler('onAfterFind'))
			$this->onAfterFind(new CEvent($this));
	}

	/**
	 * Calls {@link beforeFind}.
	 * This method is internally used.
	 * @since 1.0.11
	 */
	public function beforeFindInternal()
	{
		$this->beforeFind();
	}

	/**
	 * 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 $attributes list of attributes that need to be saved. Defaults to null,
	 * meaning all attributes that are loaded from DB will be saved.
	 * @return boolean whether the attributes are valid and the record is inserted successfully.
	 * @throws CException if the record is not new
	 */
	public function insert($attributes=null)
	{
		if(!$this->getIsNewRecord())
			throw new CDbException(Yii::t('yii','The active record cannot be inserted to database because it is not new.'));
		if($this->beforeSave())
		{
			Yii::trace(get_class($this).'.insert()','system.db.ar.CActiveRecord');
			$builder=$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;
							}
						}
					}
				}
				$this->_pk=$this->getPrimaryKey();
				$this->afterSave();
				$this->setIsNewRecord(false);
				$this->setScenario('update');
				return true;
			}
		}
		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 $attributes list of attributes that need to be saved. Defaults to null,
	 * meaning all attributes that are loaded from DB will be saved.
	 * @return boolean whether the update is successful
	 * @throws CException if the record is new
	 */
	public function update($attributes=null)
	{
		if($this->getIsNewRecord())
			throw new CDbException(Yii::t('yii','The active record cannot be updated because it is new.'));
		if($this->beforeSave())
		{
			Yii::trace(get_class($this).'.update()','system.db.ar.CActiveRecord');
			if($this->_pk===null)
				$this->_pk=$this->getPrimaryKey();
			$this->updateByPk($this->getOldPrimaryKey(),$this->getAttributes($attributes));
			$this->_pk=$this->getPrimaryKey();
			$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 and does NOT call either {@link beforeSave} or {@link afterSave}.
	 * Also note that 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 $attributes attributes to be updated. Each element represents an attribute name
	 * or an attribute value indexed by its name. If the latter, the record's
	 * attribute will be changed accordingly before saving.
	 * @return boolean whether the update is successful
	 * @throws CException if the record is new or any database error
	 */
	public function saveAttributes($attributes)
	{
		if(!$this->getIsNewRecord())
		{
			Yii::trace(get_class($this).'.saveAttributes()','system.db.ar.CActiveRecord');
			$values=array();
			foreach($attributes as $name=>$value)
			{
				if(is_integer($name))
					$values[$value]=$this->$value;
				else
					$values[$name]=$this->$name=$value;
			}
			if($this->_pk===null)
				$this->_pk=$this->getPrimaryKey();
			if($this->updateByPk($this->getOldPrimaryKey(),$values)>0)
			{
				$this->_pk=$this->getPrimaryKey();
				return true;
			}
			else
				return false;
		}
		else
			throw new CDbException(Yii::t('yii','The active record cannot be updated because it is new.'));
	}

	/**
	 * Saves one or several counter columns for the current AR object.
	 * Note that this method differs from {@link updateCounters} in that it only
	 * saves the current AR object.
	 * An example usage is as follows:
	 * <pre>
	 * $postRecord=Post::model()->findByPk($postID);
	 * $postRecord->saveCounters(array('view_count'=>1));
	 * </pre>
	 * Use negative values if you want to decrease the counters.
	 * @param array $counters the counters to be updated (column name=>increment value)
	 * @return boolean whether the saving is successful
	 * @see updateCounters
	 * @since 1.1.8
	 */
	public function saveCounters($counters)
	{
		Yii::trace(get_class($this).'.saveCounters()','system.db.ar.CActiveRecord');
		$builder=$this->getCommandBuilder();
		$table=$this->getTableSchema();
		$criteria=$builder->createPkCriteria($table,$this->getOldPrimaryKey());
		$command=$builder->createUpdateCounterCommand($this->getTableSchema(),$counters,$criteria);
		if($command->execute())
		{
			foreach($counters as $name=>$value)
				$this->$name=$this->$name+$value;
			return true;
		}
		else
			return false;
	}

	/**
	 * 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(!$this->getIsNewRecord())
		{
			Yii::trace(get_class($this).'.delete()','system.db.ar.CActiveRecord');
			if($this->beforeDelete())
			{
				$result=$this->deleteByPk($this->getPrimaryKey())>0;
				$this->afterDelete();
				return $result;
			}
			else
				return false;
		}
		else
			throw new CDbException(Yii::t('yii','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()
	{
		Yii::trace(get_class($this).'.refresh()','system.db.ar.CActiveRecord');
		if(!$this->getIsNewRecord() && ($record=$this->findByPk($this->getPrimaryKey()))!==null)
		{
			$this->_attributes=array();
			$this->_related=array();
			foreach($this->getMetaData()->columns as $name=>$column)
			{
				if(property_exists($this,$name))
					$this->$name=$record->$name;
				else
					$this->_attributes[$name]=$record->$name;
			}
			return true;
		}
		else
			return false;
	}

	/**
	 * Compares current active record with another one.
	 * The comparison is made by comparing table name and the primary key values of the two active records.
	 * @param CActiveRecord $record record to compare to
	 * @return boolean whether the two active records refer to the same row in the database table.
	 */
	public function equals($record)
	{
		return $this->tableName()===$record->tableName() && $this->getPrimaryKey()===$record->getPrimaryKey();
	}

	/**
	 * Returns the primary key value.
	 * @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;
	}

	/**
	 * Sets the primary key value.
	 * After calling this method, the old primary key value can be obtained from {@link oldPrimaryKey}.
	 * @param mixed $value the new primary key value. If the primary key is composite, the new value
	 * should be provided as an array (column name=>column value).
	 * @since 1.1.0
	 */
	public function setPrimaryKey($value)
	{
		$this->_pk=$this->getPrimaryKey();
		$table=$this->getMetaData()->tableSchema;
		if(is_string($table->primaryKey))
			$this->{$table->primaryKey}=$value;
		else if(is_array($table->primaryKey))
		{
			foreach($table->primaryKey as $name)
				$this->$name=$value[$name];
		}
	}

	/**
	 * Returns the old primary key value.
	 * This refers to the primary key value that is populated into the record
	 * after executing a find method (e.g. find(), findAll()).
	 * The value remains unchanged even if the primary key attribute is manually assigned with a different value.
	 * @return mixed the old 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.
	 * @since 1.1.0
	 */
	public function getOldPrimaryKey()
	{
		return $this->_pk;
	}

	/**
	 * Sets the old primary key value.
	 * @param mixed $value the old primary key value.
	 * @since 1.1.3
	 */
	public function setOldPrimaryKey($value)
	{
		$this->_pk=$value;
	}

	/**
	 * Performs the actual DB query and populates the AR objects with the query result.
	 * This method is mainly internally used by other AR query methods.
	 * @param CDbCriteria $criteria the query criteria
	 * @param boolean $all whether to return all data
	 * @return mixed the AR objects populated with the query result
	 * @since 1.1.7
	 */
	protected function query($criteria,$all=false)
	{
        $this->beforeFind();
		$this->applyScopes($criteria);
		if(empty($criteria->with))
		{
			if(!$all)
				$criteria->limit=1;
			$command=$this->getCommandBuilder()->createFindCommand($this->getTableSchema(),$criteria);
			return $all ? $this->populateRecords($command->queryAll(), true, $criteria->index) : $this->populateRecord($command->queryRow());
		}
		else
		{
			$finder=new CActiveFinder($this,$criteria->with);
			return $finder->query($criteria,$all);
		}
	}

	/**
	 * Applies the query scopes to the given criteria.
	 * This method merges {@link dbCriteria} with the given criteria parameter.
	 * It then resets {@link dbCriteria} to be null.
	 * @param CDbCriteria $criteria the query criteria. This parameter may be modified by merging {@link dbCriteria}.
	 * @since 1.0.12
	 */
	public function applyScopes(&$criteria)
	{
		if(!empty($criteria->scopes))
		{
			$scs=$this->scopes();
			$c=$this->getDbCriteria();
			foreach((array)$criteria->scopes as $k=>$v)
			{
				if(is_integer($k))
				{
					if(is_string($v))
					{
						if(isset($scs[$v]))
						{
							$c->mergeWith($scs[$v],true);
							continue;
						}
						$scope=$v;
						$params=array();
					}
					else if(is_array($v))
					{
						$scope=key($v);
						$params=current($v);
					}
				}
				else if(is_string($k))
				{
					$scope=$k;
					$params=$v;
				}

				call_user_func_array(array($this,$scope),(array)$params);
			}
		}

		if(isset($c) || ($c=$this->getDbCriteria(false))!==null)
		{
			$c->mergeWith($criteria);
			$criteria=$c;
			$this->_c=null;
		}
	}

	/**
	 * Returns the table alias to be used by the find methods.
	 * In relational queries, the returned table alias may vary according to
	 * the corresponding relation declaration. Also, the default table alias
	 * set by {@link setTableAlias} may be overridden by the applied scopes.
	 * @param boolean $quote whether to quote the alias name
	 * @param boolean $checkScopes whether to check if a table alias is defined in the applied scopes so far.
	 * This parameter must be set false when calling this method in {@link defaultScope}.
	 * An infinite loop would be formed otherwise.
	 * @return string the default table alias
	 * @since 1.1.1
	 */
	public function getTableAlias($quote=false, $checkScopes=true)
	{
		if($checkScopes && ($criteria=$this->getDbCriteria(false))!==null && $criteria->alias!='')
			$alias=$criteria->alias;
		else
			$alias=$this->_alias;
		return $quote ? $this->getDbConnection()->getSchema()->quoteTableName($alias) : $alias;
	}

	/**
	 * Sets the table alias to be used in queries.
	 * @param string $alias the table alias to be used in queries. The alias should NOT be quoted.
	 * @since 1.1.3
	 */
	public function setTableAlias($alias)
	{
		$this->_alias=$alias;
	}

	/**
	 * Finds a single active record with the specified condition.
	 * @param mixed $condition 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 $params parameters to be bound to an SQL statement.
	 * This is only used when the first parameter is a string (query condition).
	 * In other cases, please use {@link CDbCriteria::params} to set parameters.
	 * @return CActiveRecord the record found. Null if no record is found.
	 */
	public function find($condition='',$params=array())
	{
		Yii::trace(get_class($this).'.find()','system.db.ar.CActiveRecord');
		$criteria=$this->getCommandBuilder()->createCriteria($condition,$params);
		return $this->query($criteria);
	}

	/**
	 * Finds all active records satisfying the specified condition.
	 * See {@link find()} for detailed explanation about $condition and $params.
	 * @param mixed $condition query condition or criteria.
	 * @param array $params parameters to be bound to an SQL statement.
	 * @return array list of active records satisfying the specified condition. An empty array is returned if none is found.
	 */
	public function findAll($condition='',$params=array())
	{
		Yii::trace(get_class($this).'.findAll()','system.db.ar.CActiveRecord');
		$criteria=$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 $pk 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 $condition query condition or criteria.
	 * @param array $params parameters to be bound to an SQL statement.
	 * @return CActiveRecord the record found. Null if none is found.
	 */
	public function findByPk($pk,$condition='',$params=array())
	{
		Yii::trace(get_class($this).'.findByPk()','system.db.ar.CActiveRecord');
		$prefix=$this->getTableAlias(true).'.';
		$criteria=$this->getCommandBuilder()->createPkCriteria($this->getTableSchema(),$pk,$condition,$params,$prefix);
		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 $pk 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 $condition query condition or criteria.
	 * @param array $params parameters to be bound to an SQL statement.
	 * @return array the records found. An empty array is returned if none is found.
	 */
	public function findAllByPk($pk,$condition='',$params=array())
	{
		Yii::trace(get_class($this).'.findAllByPk()','system.db.ar.CActiveRecord');
		$prefix=$this->getTableAlias(true).'.';
		$criteria=$this->getCommandBuilder()->createPkCriteria($this->getTableSchema(),$pk,$condition,$params,$prefix);
		return $this->query($criteria,true);
	}

	/**
	 * Finds a si