partial void DeleteBao(Bao instance);
 partial void UpdateBao(Bao instance);
 private void detach_Baos(Bao entity)
 {
     this.SendPropertyChanging();
     entity.LoaiBao = null;
 }
 partial void InsertBao(Bao instance);
 private void attach_Baos(Bao entity)
 {
     this.SendPropertyChanging();
     entity.LoaiBao = this;
 }