private void attach_Phongs(Phong entity)
 {
     this.SendPropertyChanging();
     entity.Khoa = this;
 }
 partial void DeletePhong(Phong instance);
 partial void InsertPhong(Phong instance);
 partial void UpdatePhong(Phong instance);
 private void detach_Phongs(Phong entity)
 {
     this.SendPropertyChanging();
     entity.Khoa = null;
 }