Re (tilly) 2: Tricks with DBI

[tilly]

This is documented in eval. Here is how it works:

eval {call_function_that_may_die()};
if ($@) {
  # This is your error case
  print "Caught a die saying '$@'\n";
}

[htoug]

Instead of using die, you can unset $dbh->{RaiseError} locally and use the other C-like error check.

Ths is usefull when you have a SQL-statement that can fail, but where you don't want to die because of the failure. (I have used it when dropping temporary tables, that perhaps aren't there and other suchlike tings).

The code looks like this:

my $dbh=DBI->connect(....{RaiseError=>1}) or die...
my $sth=$dbh->prepare(...);
{
   local $dbh->{RaiseError} = 0;
   $sth->execute;
   if ($sth->Errstr) {
       # handle the error
   }
}
# $dbh->{RaiseError} is back to normal here

The neat thing about setting $dbh->{RaiseError} with local is that it is automagically set back to whatever it was when you leave the block, however that is done - even if it is by way of a die, that is caught in an eval somewhere else.