partial void DeleteAsignatura(Asignatura instance);
 partial void UpdateAsignatura(Asignatura instance);
 private void detach_Asignaturas(Asignatura entity)
 {
     this.SendPropertyChanging("Asignaturas");
     entity.Alumno = null;
 }
 partial void InsertAsignatura(Asignatura instance);
 private void attach_Asignaturas(Asignatura entity)
 {
     this.SendPropertyChanging("Asignaturas");
     entity.Materia = this;
 }