At 12:59 +0200 1/13/03, Octavian Rasnita wrote:
>Hi all,
>
>I've seen the following code in MySQL cookbook:
>
> eval
> {
> # move some money from one person to the other
> $dbh->do ("UPDATE money SET amt = amt - 6 WHERE name = 'Eve'");
> $dbh->do ("UPDATE money SET amt = amt + 6 WHERE name = 'Ida'");
> # all statements succeeded; commit transaction
> $dbh->commit ( );
> };
>
> if ($@) # an error occurred
> {
> print "Transaction failed, rolling back. Error was:\n$@\n";
> # roll back within eval to prevent rollback
> # failure from terminating the script
> eval { $dbh->rollback ( ); };
> }
>
>---
>
>Well, I don't understand why I need to check if $@ is true or false.
>If there wasn't any error, and the program should not rollback, in fact it
>could give the rollback command because it won't produce any effect after
>the commit command was given.
>
>Am I wrong?
That's true, but don't you think it's a little confusing to write
code that issues a rollback back after a successful transaction?
It's also an additional statement that in that case is unnecessary
to issue, so what you suggest would be less efficient.
>
>
>Teddy,
>Teddy's Center: http://teddy.fcc.ro/
>Email: orasnita@stripped
