src/Storage/Db.php
public function has($uid) {
        $options = $this->getOptions();
        $stmt = $this->adapter->query(sprintf('SELECT %s FROM %s WHERE %s = "%s"', $options['column_value'], $options['table'], $options['column_key'], $uid), Adapter::QUERY_MODE_EXECUTE);
        return $stmt->count() > 0;
    }
public function has($uid) {
        $options = $this->getOptions();
        $stmt = $this->adapter->query(sprintf('SELECT %s FROM %s WHERE %s = "%s"', $options['column_value'], $options['table'], $options['column_key'], $uid), Adapter::QUERY_MODE_EXECUTE);
        return $stmt->count() > 0;
    }
Test if has datas with $uid key
@param mixed $uid
@return boolean