my $sql_query = <<"_EOF";
    UPDATE
        gaestebuch
    SET
        Nachricht = ?,
        Name = ?,
        Wohnort = ?,
        Homepage = ?,
        Titel = ?
_EOF

my $sth = $dbh->prepare( $sql_query );
$sth->execute( $nachricht, $name, $wohnort, $homepage, $titel );