Zebra_Session::write PHP Méthode

    function write($session_id, $session_data)
    {
        // insert OR update session's data - this is how it works:
        // first it tries to insert a new row in the database BUT if session_id is already in the database then just
        // update session_data and session_expire for that specific session_id
        // read more here http://dev.mysql.com/doc/refman/4.1/en/insert-on-duplicate.html
        $result = $this->_mysql_query('

            INSERT INTO
                ' . $this->table_name . ' (
                    session_id,
                    hash,
                    session_data,
                    session_expire
                )
            VALUES (
                "' . $this->_mysql_real_escape_string($session_id) . '",
                "' . $this->_mysql_real_escape_string(md5(($this->lock_to_user_agent && isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : '') . ($this->lock_to_ip && isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '') . $this->security_code)) . '",
                "' . $this->_mysql_real_escape_string($session_data) . '",
                "' . $this->_mysql_real_escape_string(time() + $this->session_lifetime) . '"
            )
            ON DUPLICATE KEY UPDATE
                session_data = "' . $this->_mysql_real_escape_string($session_data) . '",
                session_expire = "' . $this->_mysql_real_escape_string(time() + $this->session_lifetime) . '"

        ') or die($this->_mysql_error());
        // if anything happened
        if ($result) {
            // note that after this type of queries, mysqli_affected_rows() returns
            // - 1 if the row was inserted
            // - 2 if the row was updated
            // if the row was updated
            // return TRUE
            if (@$this->_mysql_affected_rows() > 1) {
                return true;
            } else {
                return '';
            }
        }
        // if something went wrong, return false
        return false;
    }