partial void Deletetlb_lop(tlb_lop instance);
 partial void Updatetlb_lop(tlb_lop instance);
 private void detach_tlb_lops(tlb_lop entity)
 {
     this.SendPropertyChanging();
     entity.tlb_nganh = null;
 }
 partial void Inserttlb_lop(tlb_lop instance);
 private void attach_tlb_lops(tlb_lop entity)
 {
     this.SendPropertyChanging();
     entity.tlb_nganh = this;
 }