Yii Model Relation 'on' option to join the tables in yii Model relation

Question

What is going on with me on Yii model Relation ! I have 2 Models:

  `Question and Video`, 

I am saving

`question_id` in `Video model as foreign key`, 

Now I want to build a relation in Question model like this:

      'video'=>array(self::HAS_MANY, 'Video', '', 'on'=>'video.question_id=id'),

and then in clistview I am showing :

    if (!empty($data->video))
    echo CHtml::encode($data->video->video_title);

but nothing happen there, what's wrong with my code?

Answer 1

You have your relation setup incorrectly:

'video'=>array(self::HAS_MANY, 'Video', 'question_id'),
//this compares Video->question_id to Question->primary_key

You don't need to specify on , it uses the third criteria question_id and compares it to the primary key of your Question model since you are specifying HAS_MANY . If you had a relation of BELONGS_TO the third criteria refers to the attribute in that model and compares it to the foreign key in the other model. So if you had the opposite relationship setup on your Video model it would be:

'question'=>array(self::BELONGS_TO,'Question','question_id'),
//this compares Video->question_id to Question->primary_key

Also you currently have

echo CHtml::encode($data->video->video_title);

Since you are specifying that it HAS_MANY $data->video will be an array of Video instances. So you have two options just use the first element in the array data->video[0]->video_title or convert HAS_MANY into HAS_ONE then it will only make one connection and not look for multiples.