как сделать что-бы совподение не допускались...

 TLocateOptions Options;
 Options.Clear();
 Options << loPartialKey;
if(ADOQuery1->Locate("Invent_Number",ValueListEditor1->Cells[1][1],Options))
         {
          AnsiString bw = "Òàêîé èíâåíòàðíûé íîìåð óæå åñòü â áàçå äàííûõ!!! \n\n" + IntToStr(ADOQuery1->FieldByName("Invent_Number")->AsInteger)+" - "
          +ADOQuery1->FieldByName("Number_in_Lan")->AsString+" - "
          +ADOQuery1->FieldByName("Department")->AsString+" - "
          +ADOQuery1->FieldByName("Processor")->AsString+" - "
          +ADOQuery1->FieldByName("Memory")->AsString+" - "
          +ADOQuery1->FieldByName("HDD")->AsString+" - "
          +ADOQuery1->FieldByName("Room")->AsString+"\n\n"
          + "Ââåäèòå äðóãîé èíâåíòàðíûé íîìåð";
 
          if(Application->MessageBox(bw.c_str(),"Âíèìàíèå",MB_ICONWARNING)==IDOK)
         {
          RunOptionsZapros();
          LocateStroki();
          ADOQuery1->Locate("Invent_Number",save,Options);
          ValueListEditor1->SetFocus();
          ValueListEditor1->Row = 1;
         }

LocateStroki();

Form1->ADOCommand1->CommandText = "Insert Into Student(numeprenume,nrcarnet,adresa,idgr,tipstud)values ( :b, :c, :d,:e,:f)";
 
Form1->ADOCommand1->Parameters->ParamByName("b")->Value=Edit1->Text;
Form1->ADOCommand1->Parameters->ParamByName("c")->Value=StrToInt(Edit2->Text);
Form1->ADOCommand1->Parameters->ParamByName("d")->Value=Edit3->Text;
Form1->ADOCommand1->Parameters->ParamByName("e")->Value=DBLookupComboBox1->KeyValue;
Form1->ADOCommand1->Parameters->ParamByName("f")->Value=ComboBox1->Text;
 
Form1->ADOCommand1->Execute();
 
Form1->ADOTable1->Close();
Form1->ADOTable1->Open();
 
Form1->ADOQuery1->Close();
Form1->ADOQuery1->Open();
 
 
ShowMessage("добавлен успешно");
Edit1->Clear();
Edit2->Clear();
Edit3->Clear();