🚀 go-pugleaf

Hello all,

In BCB4 Unleashed, a technique of opening a query in a thread is
demonstrated in a two-tier app.  I am trying to apply this technique in
a three-tier app, with limited success.  I have a RDM with a TDatabase
and a TSession set to AutoSessionName.  When I open a query from this
RDM in a thread I receive the following error: "General SQL error:
Connection does not exist."  Funny thing, the client still shows the
query properly after the error.  What is this error trying to tell me?

Following is the code for the thread object I am using.  I have tried
not disconnecting and reconnecting the provider, to no avail.

__fastcall TQueryThread::TQueryThread( TProvider* Provider ) : TThread(
true )
{
  FProvider = Provider;
  FreeOnTerminate = true;
  Resume();
}

void __fastcall TQueryThread::Execute()
{
  try {
    FQuery = (TQuery *)FProvider->DataSet;
    Synchronize( DisconnectProvider );
    FQuery->Open();  // <--- error right here
    Synchronize( ConnectProvider );
  }
  catch (Exception* E) {
    FQueryException = E;
    Synchronize( ShowQryError );
  }
}

void __fastcall TQueryThread::DisconnectProvider()
{
  FProvider->DataSet = NULL;
}

void __fastcall TQueryThread::ConnectProvider()
{
  FProvider->DataSet = FQuery;
}

void __fastcall TQueryThread::ShowQryError()
{
  Application->ShowException( FQueryException );
}