php - Yii - Self Referencing Table -

this category table

id category  parent_category_id 1  animal      null 2  vegetable   null 3  mineral     null 4  doggie      1 5  potato      2 6  hunting     4 

my yii grid view shows parent category id instead of name. how can display parent category name in grid view.

<?php $this->widget('zii.widgets.grid.cgridview', array(     'id'=>'category-grid',     'dataprovider'=>$model->search(),     'filter'=>$model,     'columns'=>array(         'id',         'category',         'parent_category_id',         array(             'class'=>'cbuttoncolumn',         ),     ), )); ?> 

what changes have make in above code. thanks.

first step - define relation in model class:

public function relations() {     return array(         'parent'=>array(self::belongs_to, 'category', 'parent_category_id'),     ); } 

where category - name of ar model class, parent_category_id - foreign key referencing itself.

step 2 - cgridview, columns attribute:

... 'columns'=>array(     'id',     'category',     array(         'name'=>'parent category', // col title         'value'=>function (category $data){             if($data->parent_category_id)                 return $data->parent->category; // "parent" - relation name, defined in "relations" method               return "-= root category =-";           }     ), ) ... 

note: code above requires php version>=5.3. otherwise have avoid using anonymous function