private void detach_HOADONs(HOADON entity)
 {
     this.SendPropertyChanging();
     entity.KHACHHANG = null;
 }
 private void attach_HOADONs(HOADON entity)
 {
     this.SendPropertyChanging();
     entity.KHACHHANG = this;
 }
 partial void UpdateHOADON(HOADON instance);
 partial void DeleteHOADON(HOADON instance);
 partial void InsertHOADON(HOADON instance);