php-如何在yii框架中为州和城市创建和查看关系

我是yii框架的入门者,我找不到如何显示关联的视图.

我这样尝试：

my model (Cities.PHP)
    public function relations()
        {
            // NOTE: you may need to adjust the relation name and the related
            // class name for the relations automatically generated below.
            return array(
                'states' => array(self::BELONGS_TO, 'State', 'state_id')
            );
        }

我的查看代码如下：

<?PHP 
    $cities = Cities::model()->findAll(); 
    foreach($cities as $city){
        $state=States::model()->findByPk($city->id);?>
        <tr>
            <td><?PHP echo cities.state_id;?></td>
        </tr>
<?PHP } ?>

但是我得到了未定义索引城市的错误.我该如何解决该错误？

解决方法:

这将起作用：

<?PHP
$cities = Cities::model()->findAll();
foreach($cities as $city) {
?>
<tr>
    <td><?PHP echo $city->states->state_name;?></td>
</tr>
<?PHP
}
?>

该模型：

public function relations()
        {
            // NOTE: you may need to adjust the relation name and the related
            // class name for the relations automatically generated below.
            return array(
                'states' => array(self::BELONGS_TO, 'State', 'state_id')
            );
        }

这里,

状态是关系名称

BELONGS_TO是关系类型

状态是它所连接的模型

state_id是外键