class Identifier extends DataObject {

    static $db = array(
        'Name' => 'Varchar(255)',
        'Inc' => 'Int'
    );

    public static function next_id($name) {
        if ($name) {
            $id = DataObject::get_one('Identifier', "Name = '$name'");

            if ($id) {
                $id->Inc+=1;
            } else {
                $id = new Identifier();
                $id->write();
                $id->Name = $name;
                $id->Inc = 20;
            }

            $id->write();
            return $id->Inc;
        }
    }

}