A Database Example 

• Raising exceptions - the easy way

my $attr = { AutoCommit => 0, RaiseError => 1, PrintError => 0 };
my $dsn  = 'dbi:Pg:dbname=products';

sub get_categories_by_mgr {
  my($prod_mgr_id) = @_;

  my $dbh = DBI->connect($dsn, $user, $pswd, $attr);
  my $sql = 'SELECT * FROM prod_category WHERE prod_mgr_id = ?';
  my $sth = $dbh->prepare($sql);
  $sth->execute($prod_mgr_id);

  my @categories;
  while(my $row = $sth->fetchrow_arrayref) {
    push @categories, $row;
  }

  $dbh->disconnect;

  return \@categories;
}