如何使用Active Record进行关联查询

1 class News extends CActiveRecord2 {3 /**4 * @return array relational rules.5 */6 public function relations()7 {8 // NOTE: you may need to adjust the relation name and the related9 // class name for the relations automatically generated below.10 return array(11 ‘type’ => array(self::BELONGS_TO, ‘NewsType’, ‘type_id’)12 );13 }14 }1516 // 在News设置了关联NewsType;17 $news=News::model()->findByPk(77);1819 // 获取新闻的类别(type): 此处将执行一个关联查询。惰式加载20 $type=$post->type;2122 // 如果调用N个新闻查询时,例如23 $dataProvider=new CActiveDataProvider(‘News’);2425 // 或者26 $data = News::model()->findAll();2728 // 懒惰式就不高效,29 // 这时应该使用如下方式进行预加载30 $dataProvider=new CActiveDataProvider(‘News’,31 array(‘criteria’ => new CDbCriteria(array(‘with’ => array(‘type’)));32 // 或者33 $data=News::model()->with(‘type’)->findAll();