🚀 go-pugleaf

Try to use TADOConnection component - the same for both queries. MS Jet uses
"lazy writes" and changes become visible to other users (other programs,
other connections) after 5 seconds.

SystemQuery->Connection = ADOConnection1;
instead of
SystemQuery->ConnectionString = "...";

//------------------------------------------
Regards,
Vassiliev V. V.
http://www.managed-vcl.com - using .Net objects in Delphi for Win32 +
ADO.Net
http://www.oledbdirect.com - The fastest way to access MS SQL Server,
MS Jet (Access) and Interbase (through OLEDB)

"Drew" <aemsley@brightwell.org.uk> �������/�������� � �������� ���������:
news:413d754c@newsgroups.borland.com...
> I'm using BCB6 Professional, MS Access 2000 and MS Jet 4.0.
>
> If I do an UPDATE on a able, followed immediately afterwards by a SELECT
on
> the same fields in the same table, the values returned by the SELECT do
not
> show the values that were updated by the UPDATE command.
>
> However, if I step through the code in the debugger or explicitly wait for
a
> period, then the new values are returned by the SELECT.
>
> I thought that ADO immediately wrote the new values to the table, or do I
> have to wait for the ExecSQL command to complete?
>
> The code in question is below:
>
>
//--------------------------------------------------------------------------
> ---------------------------------------
> void __fastcall WbSvrThread::WebServerUpdateSystemParameters(TIdCommand*
> ASender)
> {
> TADOQuery* SystemQuery;
>
>     try
>     {
>         SystemQuery = new TADOQuery(NULL);
>         SystemQuery->ConnectionString =
> "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Program Files\\Hilltop
> Monitoring System\\hilltop.mdb;Mode=ReadWrite|Share Deny None;Persist
> Security Info=False";
>
>         sysParams_t replyBuffer;
>         AnsiString sqlString;
>
>         sqlString.sprintf("UPDATE SystemTable SET
IPConnectRetriesNormal=%s,
> IPConnectRetriesFailed=%s, IPConnectTimeout=%s, TelRetriesNormal=%s,
> TelRetriesFailed=%s, TelTimeout=%s, NormalScheduleFrequency=%s,
> AlarmScheduleFrequency=%s, RtrFrequency=%s",
>                                        ASender->Params->Strings[0],
> ASender->Params->Strings[1], ASender->Params->Strings[2],
>                                        ASender->Params->Strings[3],
> ASender->Params->Strings[4], ASender->Params->Strings[5],
>                                        ASender->Params->Strings[6],
> ASender->Params->Strings[7], ASender->Params->Strings[8]);
>         SystemQuery->SQL->Clear();
>         SystemQuery->SQL->Add(sqlString);
>         SystemQuery->Prepared = true;
>
>         AnsiString msgType;
>
>         try
>         {
>             SystemQuery->ExecSQL();
>
>             msgType=ACK;
>
>             // Send the confirmation to the webserver
>             ASender->Thread->Connection->WriteLn(msgType);
>
>             ParentForm->FindScanIntervals();
>         }
>         catch (Exception &e)
>         {
>             sprintf(msg, "Updating system parameters in database failed:
> exception = %s", e.Message);
>             Log(0, msg);
>
>             msgType=NACK;
>
>             // Send the negative confirmation to the webserver
>             ASender->Thread->Connection->WriteLn(msgType);
>         }
>     }
>     catch(Exception &e)
>     {
>         sprintf(msg, "WebServerUpdateSystemParams failed: exception = %s",
> e.Message);
>         Log(0, msg);
>     }
>     delete SystemQuery;
> }
>
>
> void __fastcall TForm1::FindScanIntervals(void)
> {
>     AnsiString sqlString;
>
>     sqlString.sprintf("SELECT NormalScheduleFrequency,
> AlarmScheduleFrequency, RtrFrequency FROM SystemTable");
>     ADOQuery1->SQL->Clear();
>     ADOQuery1->SQL->Add(sqlString);
>
>     try
>     {
>         ADOQuery1->Open();
>
>         if (ADOQuery1->RecordCount > 0)
>         {
>             NormalScanSchedule =
> ADOQuery1->Fields->FieldByNumber(1)->AsInteger  * 60;
>             AlarmScanSchedule =
> ADOQuery1->Fields->FieldByNumber(2)->AsInteger * 60;
>             RouterFrequency =
ADOQuery1->Fields->FieldByNumber(3)->AsInteger
> * 60;
>         }
>
>         ADOQuery1->Close();
>
>     }
>     catch(...)
>     {
>         Log("SQL Update failed");
>     }
>
> }
>
>
> Any ideas/suggestions gratefully received.
>
> Andrew
>
>