    public function read($sessionId)
    {
        $dbData = $this->getCollection()->findOne(array(
            $this->options['id_field'] => $sessionId,
            $this->options['expiry_field'] => array('$gte' => new \MongoDate()),
        ));

        return null === $dbData ? '' : $dbData[$this->options['data_field']]->bin;
    }
The software constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.