sub get_auto_increment {
	my ($dbh, $table) = @_;

	my $sth = $dbh->prepare("show columns from $table");
	$sth->execute;

	my $ref;
	while ($ref = $sth->fetchrow_hashref) {
		if ($ref->{'Extra'} eq 'auto_increment') {
			$sth->finish;
			return $ref->{'Field'};
		}
	}

	$sth->finish;
	return undef;
}