my $dbh = $base::dbh; # get a database handle

eval {
  # lots of inserts, updates, etc...
};
if ($@) {
  my $err = $@;
  eval { $dbh->rollback };
  # display formatted errors
  $base::showerrors(
    ($base::debug ? $err : "database related error"),
    ($@ ? " error performing rollback\n"
        : " rollback performed successfully\n")
  );
}