private void detach_DuAns(DuAn entity)
 {
     this.SendPropertyChanging();
     entity.PhongBan = null;
 }
 private void attach_DuAns(DuAn entity)
 {
     this.SendPropertyChanging();
     entity.PhongBan = this;
 }
 partial void UpdateDuAn(DuAn instance);
 partial void DeleteDuAn(DuAn instance);
 partial void InsertDuAn(DuAn instance);