保存模型实例在Yii中不起作用

我有这些代码，但save()方法不起作用。有什么问题吗?

public function rules()
{
    return array(
        array('name', 'required'),
                    array('name site_id', 'unique'),
                    array('status, site_id', 'numerical', 'integerOnly'=>true),
        array('name, author', 'length', 'max'=>50),
        array('version', 'length', 'max'=>10),
                    array('config_content', 'safe'),
        array('id, name, author, version, status, config_content, site_id', 'safe', 'on'=>'search'),
    );
}

和

$new_row = new Module;
$new_row->name = 'test';
$new_row->config_content = 'asasfdfd';
$new_row->site_id = 2;
$new_row->status = 0;
if($new_row->save())
   echo 'Yes!';
else
   echo 'No!';