Using starttransaction with C++ builder 6.0 and SDAC

[boutwater]

Hello,
I wanted to know the proper way to code using the starttransaction, commit/rollback functionality of the SDAC.

Code: Select all

    case 2: {  // custom Method == 2
      Refresh();
      MSQuery->SQL->Clear();
      MSQuery->SQL->Add(DB->CustomQueryString);
      try {
        MSQuery->Execute();
      } catch (EMSError &E) {
        Answer = false;
        char ErrorMsg[2048];
        UpString(ErrorMsg,E.Message.c_str());
        if (strstr(ErrorMsg,"PRIMARY KEY CONSTRAINT") == NULL) {
          sprintf(ErrorMsg,"Key Convert Error: %s",E.Message.c_str());
          DB->DBErrorNote(ErrorMsg);
          iSET->WriteToDBLog(ErrorMsg);
        }
      }
      if (MSQuery->RecordCount > 0) {
        Data.ErrorCodeID = MSQuery->Fields->Fields[0]->AsString;
        Data.ToDescription = MSQuery->Fields->Fields[1]->AsString;
        Answer = true;
      } else {
        Data.CartonID = "";
      }
      MSQuery->Close();
      break;
    }  // END of Method 2

In the above code, how would I add Starttransaction, commit and rollback?

A secondary question is, will this adversly affect other queries running against this database? The above function could be called from multiple places and multiple applications against the database. Thank you in advance for your help.

I'm using Borland C++ Builder 6.0 pro and the sdac 4.8.

Ben

[AndreyZ]

Hello,

Here is a code example:

Code: Select all

MSQuery->SQL->Add(DB->CustomQueryString);
MSQuery->Connection->StartTransaction();
try {
  MSQuery->Execute();
  MSQuery->Connection->Commit();
} catch (EMSError &E) {
  MSQuery->Connection->Rollback();
  Answer = false;
...
}

Using transactions affects queries that read or write data to the same tables at the same time. Depending on the transaction isolation level, one query will see or will no see changes that are being made by another query. For more information about transaction isolation levels, please refer to http://msdn.microsoft.com/en-us/library/ms173763.aspx