public function getIdClassSubject($idClass, $idSubject, $idFacuty)
 {
     $classSubject = ClassSubject::model()->find('ID_Class=:idClass AND ID_Subject=:idSubject AND ID_Facuty=:idFacuty', array('idClass' => $idClass, 'idSubject' => $idSubject, 'idFacuty' => $idFacuty));
     return $classSubject->ID;
 }
 /**
  * Returns the data model based on the primary key given in the GET variable.
  * If the data model is not found, an HTTP exception will be raised.
  * @param integer $id the ID of the model to be loaded
  * @return ClassSubject the loaded model
  * @throws CHttpException
  */
 public function loadModel($id)
 {
     $model = ClassSubject::model()->findByPk($id);
     if ($model === null) {
         throw new CHttpException(404, 'The requested page does not exist.');
     }
     return $model;
 }