private function getRandomId($entityClass, $annotation)
    {
        if ('int' === $annotation->type || 'integer' === $annotation->type) {
            return mt_rand(pow(10, $annotation->length - 1), pow(10, $annotation->length) - 1);
        }

        return substr(hash('sha256', sprintf('%s - %s - %s', microtime(), $entityClass, uniqid())), 0, $annotation->length);
    }