partial void DeletesubjectTeacher(subjectTeacher instance);
 partial void InsertsubjectTeacher(subjectTeacher instance);
 partial void UpdatesubjectTeacher(subjectTeacher instance);
 public bool isSubjectTeachersAdded( int subjectID, int teacherID )
 {
     subjectTeacher st = new subjectTeacher() {
         subject_ID = subjectID,
         teacher_ID = teacherID
     };
     try {
         MOE_DB.subjectTeachers.InsertOnSubmit( st );
         MOE_DB.SubmitChanges();
         return true;
     }
     catch (Exception ex) {
         return false;
     }
 }