However, on the subsequent 4 $dbh->do statements you make no such tests.

... and with a little bit of RTFM, none of those tests is needed. Change

my $dbh = DBI->connect($dsn, $user, $password)
  or die "Couldn't connect to database: " . DBI->errstr;
[download]

to

my $dbh = DBI->connect($dsn, $user, $password, { RaiseError => 1, Prin
+tError => 0 })
  or die "Couldn't connect to database: " . DBI->errstr;
[download]

and DBI will automatically check for errors, no manual checks needed.

Alexander