function create_db_instance()
{
    require 'db_settings.php';
    try {
        $db = new CMySQL();
        $db->connect($db_server, $db_username, $db_password);
        $db->selectDatabase($db_database);
        return $db;
    } catch (Exception $e) {
        echo 'Virhe tietokantayhteydessä!';
    }
    return null;
}