Zeos transaction error - "invalid operation in non AutoCommit mode"?
lazarus / 16-Databases

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JD · 2011-03-02 01:11

Hi there everyone,

I am using the code below to manage transactions in my application.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.DoTransaction(DataSet: TDataSet);begin  with ZConnection1 do 
begin    if not AutoCommit then    begin      StartTransaction;    
//Gives me an error 'invalid operation in non AutoCommit mode'     
try        Commit;      except        Rollback;      end;     
Dataset.Refresh;    end;  end;end; What I find odd is that I get an
error "invalid operation in non AutoCommit mode" everytime I try to
update the database. I later discovered that the error is due to the
line

Code: [Select]StartTransaction

Once I comment out this line, everything works fine.

Is this normal? Why should the explicit call to "StartTransaction" on
a Zeos connection generate an error? Does setting "AutoCommit :=
False" implicitly start a transaction? Is it one or the other but not
the two at the same time?

Thanks for your assistance.

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pierre.se.pos · 2011-03-02 05:47

Hi

Please see the entry on StartTransaction on the following page:
http://zeos.firmos.at/kb.php?mode=article&k=6

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Zoran · 2011-03-02 08:52

Despite what you can expect, you must not use StartTransaction when
AutoCommit is False!

This is how AutoCommit property actually works in Zeos:
 when AutoCommit is True, then the transactions are commited
automatically after each executed SQL statement, but you can use the
StartTransaction command explicitely to prevent this auto commiting,
until you explicitely call Commit. when AutoCommit is False, you
should not call StartTransaction. Then the transaction is started
automatically, but it will not commit automatically after every
executed statement.

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JD · 2011-03-02 09:10

Thanks a lot pierre.se.pos & Zoran. I now understand how to use
AutoCommit better.