I have the list of array from my model

CHtml::listData($tags, 'id', 'post_id')

In model

* @return array relational rules.
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(
'post' => array(self::BELONGS_TO, 'Post', 'post_id'),

I want to get listData like this

CHtml::listData($tags, 'id', /*here is syntax to get relation name*/)