public function rules()
{
// NOTE: you should only define rules for those attributes that
// will receive user inputs.
return array(array('worklist_definition_id, key', 'required'), array('display_order', 'numerical', 'integerOnly' => true, 'allowEmpty' => true), array('id, worklist_definition_id, key', 'safe', 'on' => 'search'));
}