Lazarus 0.9.30.2 How to destroy a dynamically created
TMySQL51Connection? ERROR
lazarus / 16-Databases

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lazguy · 2012-02-03 01:21

Hello everybody !!!!!!!  new doubts  ;-)

On Lazarus 0.9.30 (Windows 7) and TMySQL50Connection I have the code
(and it works):

Code: [Select]    try
      ConCli := TMySQL50Connection.Create(nil);
      ConCli.HostName := ipHost;
      ConCli.port := 3306;
      ConCli.UserName := username;
      ConCli.Password := password;
      ConCli.DatabaseName := databasename;
      TranCli := TSQLTransaction.Create(nil);
      TranCli.DataBase := ConCli;
      QryCli := TSQLQuery.Create(nil);
      QryCli.DataBase := ConCli;
      QryCli.Transaction := TranCli;
      try
        ConCli.Open;
      except
        on e : exception do
        begin
          if (e.Message='Server connect failed.') then
          begin
            MessageDlg('Error',
                'Could not connect server.',mtError,
                 [mbCancel],0);
            exit;
          end;
        end;
      end;
     
          ...
         
          Code here
         
          ...
         
    finally
      QryCli.Close;
      ConCli.Close;
      QryCli.Free;
      TranCli.Free;
      ConCli.Free;
    end;

When I use the same code on Lazarus 0.9.30.2 with TMySQL51Connection I
have the following error at the line

TranCli.Free;

Debugger Exception Notification   Project Controle de Processos raised
exception class 'EDatabaseError' with message Operation cannot be
performed on an active transaction

How to solve this ?

Thank you very much in advance.

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lazguy · 2012-02-08 01:35

Well, I returned to Lazarus 0.9.30, but i don't know why i am having
the same error.

I found the site  http://mantis.freepascal.org/view.php?id=18841     I
applied the patch, but the error message continues.

So, after some tries, i discovered that if i use the method
freeinstance on both the transaction and the connection i don't have
the error and seems that the problem was solved.

So I ask: Can I use freeinstance instead of free ?

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ludob · 2012-02-08 09:30

The problem reported on mantis was caused by TSQLTransaction.Destroy
calling rollback which returned always false for mysql. Have you tried
'TranCli.commit;' before calling 'TranCli.Free;'?

Freeinstance should never be called directly. It is like pulling the
plug on your computer to shut it down.

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lazguy · 2012-02-14 14:32

Hi ludob,

excuse me for the delay, the lazarus forum was off-line the last time
i came here.

Well, I tried the commit without success. Please, do you know what can
i do ?

Can anyone help me ?

Thank you very much in advance.

I am posting a doubt about this on de generic topic asking how to
completely remove Lazarus. I will try to go back to the previous
version.