partial void DeleteDuong(Duong instance);
 partial void UpdateDuong(Duong instance);
		private void detach_Duongs(Duong entity)
		{
			this.SendPropertyChanging();
			entity.QuanHuyen = null;
		}
 partial void InsertDuong(Duong instance);
		private void attach_Duongs(Duong entity)
		{
			this.SendPropertyChanging();
			entity.QuanHuyen = this;
		}