public function addClass($code, $name, $description)
{
$class_new = new class_model();
$class_year = new ClassYear();
$class_user = new ClassUser();
$class_new->class_code = $code;
$class_new->class_name = $name;
$class_new->class_description = $description;
$class_new->save(FALSE);
$class_id = class_model::model()->findByAttributes(array('class_id' => $class_new->class_id));
$class_year->class_code = $code;
$class_year->is_active = 1;
$class_year->class_id = $class_id->class_id;
$class_year->class_year = date("Y");
$class_year->save(FALSE);
$class_user->user_id = Yii::app()->session['user_id'];
$class_user->admin_id = Yii::app()->session['user_id'];
$class_user->class_id = $class_id->class_id;
$class_user->is_active = 1;
$class_user->save(FALSE);
return $class_id->class_id;
}