public function rules()
{
// NOTE: you should only define rules for those attributes that
// will receive user inputs.
return array(array('title, description', 'required'), array('title', 'length', 'max' => 32), array('description', 'length', 'max' => 255), array('date_added, date_modified', 'safe'), array('tax_class_id, title, description, date_added, date_modified', 'safe', 'on' => 'search'));
}