I should point out that:

    my $sth = $dbh->prepare($data);
[download]

may fail if the SQL statement is syntactically incorrect. That's not the case here, since $sth->execute() succeeds afterwards, but it's a good idea to get into the habit of checking the return from prepare as well.

Disclaimer: for all I know, prepare might be a no-op for MySQL, but that's certainly not the case for other database engines. Get into the habit of doing it anyway, and you'll have less strife when you work with other dbs.