Why sometimes I get an "Invalid transaction object" exception?

Question

Is there something wrong with this code?
Sometimes I get an unhandled "Invalid transaction object" exception in it:

procedure BlaBla;
var
  TD: TDBXTransaction;
begin
  TD := SQLConnection.BeginTransaction;
  try
    SQLConnection.ExecuteDirect('some sql command');
    SQLConnection.ExecuteDirect('some sql command');
    SQLConnection.CommitFreeAndNil(TD);
  except
    SQLConnection.RollbackFreeAndNil(TD);
  end;
end;

This exception is being raised to the user, so I assume it's raised by RollbackFreeAndNil, since all rest is inside a try..except.

Should I wrap RollbackFreeAndNil with another try..except? What a mess.

I'm using Delphi 2009, DBX with Firebird 2.1 and Devart's driver.

Craig Stuntz · Answer 1 · 2009-01-07T16:15:53.510

4

What would happen if CommitFreeAndNil threw an exception?

RollbackFreeAndNil would be called. Would TD be valid then?

You're eating the exception, and hence the evidence. Don't do that; re-throw:

procedure BlaBla;
var
  TD: TDBXTransaction;
begin
  TD := SQLConnection.BeginTransaction;
  try
    SQLConnection.ExecuteDirect('some sql command');
    SQLConnection.ExecuteDirect('some sql command');
  except
    SQLConnection.RollbackFreeAndNil(TD);
    raise;
  end;
  SQLConnection.CommitFreeAndNil(TD);
end;

edited Jan 07 '09 at 16:15

answered Jan 07 '09 at 14:12

Craig Stuntz

125,891
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And when re-throwing, you could use the new inner-exception-feature, as shown by Jim McKeeth at CodeRage III. – Vegar Jan 07 '09 at 14:21
Thanks Craig, please, read again my question because I added more information after you answer. – Erick Sasse Jan 07 '09 at 15:39
Thanks, this will help to investigate the problem. – Erick Sasse Jan 07 '09 at 16:43
The problem was not related to my try..except block. – Erick Sasse Mar 03 '09 at 19:12
My first sentence: "What would happen if CommitFreeAndNil threw an exception?" Your solution: "And then I get the exception of invalid transaction object." Yup, completely unrelated! – Craig Stuntz Mar 03 '09 at 19:50

score 3 · Accepted Answer · answered Mar 03 '09 at 19:17

The problem is that SQLConnection.BeginTransaction returns nil if SQLConnection is not Connected to the database. And then I get the exception of invalid transaction object.

I never expected that. It should try to connect or raise an exception. Returning nil doesn't make sense to me.

score 1 · Answer 3 · answered Dec 02 '11 at 22:12

1

some times is that you execute varius procedures with a component like cxdbmemo and give you thats error. You have to remove that component (or somthing like this) and do your transaction normal.

answered Dec 02 '11 at 22:12

maximo

11
1

score 0 · Answer 4 · edited Dec 22 '11 at 09:21

0

SQLConnection.DBXConnection.BeginTransaction(TDBXIsolations.ReadCommitted);

edited Dec 22 '11 at 09:21

JMax

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answered Feb 25 '10 at 08:13

Adelson

1

Why sometimes I get an "Invalid transaction object" exception?

4 Answers4