Re: Re: DBI AutoCommit clarification

When Autocommit is on, instead, every statement is automatically committed, and therefore transactions are disabled, i.e. you can't rollback.

This is mostly correct. However, with MS-SQL and Sybase (and possibly others) you can still use transactions by explicitly issuing BEGIN TRAN requests in do() and/or prepare() requests.

Michael

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Re: Re: Re: DBI AutoCommit clarification by tantarbobus (Hermit) on Sep 18, 2003 at 18:43 UTC
And then there is always the `$dbh->begin_work()` method, but I don't know how many drivers support it at this time; I know that neither DBD::mysql nor DBD::Pg support it right now. Oracle? The nice thing about `$dbh->begin_work()` over `local($dbh->{AutoCommit}) = 0;` is that `$dbh->begin_work()` will not automatically commit on exiting scope which could be a bad thing if you missed catching an exception or forgot to rollback in the exception handler.	[reply] [d/l] [select]
Re: Re: Re: Re: DBI AutoCommit clarification by mpeppler (Vicar) on Sep 19, 2003 at 15:57 UTC
If you check the DBI sources, begin_work() is nothing more than `$dbh->{AutoCommit} = 0;`... The nice thing about $dbh->begin_work() over local($dbh->{AutoCommit}) = 0; is that $dbh->begin_work() will not automatically commit on exiting scope... That's a good point. My first reaction was that no driver should do that, but then I looked at my sources and realized that DBD::Sybase does indeed commit silently when AutoCommit is turned back on. I'm not sure that I like that behavior - I should probably issue a message about un-committed work at that point - if you have AutoCommit turned off you should really be forced to explicitly commit or rollback any changes, and just flipping AutoCommit back on isn't the same thing. Michael	[reply] [d/l]