class.YND360Model.php

public static function makeIdentifier($string, $entity=null) {
        $base_identifier = Model::sanitizeName($string);
        if ($entity) {
            $new_increment =
                Kohana_ORM::factory($entity)
                ->select(new Kohana_Database_Expression('substring(identifier, -1) + 1 as new_increment'))
                ->regex('identifier', $base_identifier.'[1-9][0-9]*')
                ->orderby('new_increment', 'desc')
                ->limit(1)
                ->find();
            return $base_identifier . ($new_increment->count() == 0 ? '' : $new_increment->current()->new_increment);
        } else {
            return $base_identifier;
        }
    }