How to write session to database in php

<?php
 
#
#  codeMaker Alpha 0.1.1 ( haowei.me )
#  This framework comply with the GPL license agreement
#
 
class session_handler {
   
  protected $maxlifetime = null;
  protected $dbHandle = null;
  public $config = null;
   
  public static function init($args) {
    return new self($args);
  }
   
  public function __construct($args) {
     
    $this->config = $args;
    $this->maxlifetime = get_cfg_var("session.gc_maxlifetime");
    session_set_save_handler(
    array($this, "open"),
    array($this, "close"),
    array($this, "read"),
    array($this, "write"),
    array($this, "destroy"),
    array($this, "gc"));
     
  }
   
  public function open() {
    $this->link = mysqli_connect(
    $this->config[&#39;host&#39;], 
    $this->config[&#39;user&#39;], 
    $this->config[&#39;password&#39;], 
    $this->config[&#39;database&#39;]);
    mysqli_set_charset($this->link, "utf8");
    $sql = &#39;CREATE TABLE IF NOT EXISTS `%s` (
    `session_id` varchar(255) NOT NULL,
    `session_data` text,
    `session_expires` char(10) NOT NULL,
    PRIMARY KEY (`session_id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;&#39;;
    $sql = sprintf($sql, $this->config[&#39;table&#39;]);
    mysqli_query($this->link, $sql);
    return true;
  }
   
  public function close() {
    return true;
  }
   
   
  public function read($session_id) {
    if(empty($session_id)) return null;
     
    $sql = &#39;SELECT `session_data` AS `data` FROM `%s` WHERE `session_id` = "%s" AND `session_expires` > "%u"&#39;;
    $sql = sprintf($sql, 
    mysqli_real_escape_string($this->link, $this->config[&#39;table&#39;]), 
    mysqli_real_escape_string($this->link, $session_id),
    time());
     
    $result = mysqli_query($this->link, $sql);
    $row = mysqli_fetch_assoc($result);
    return $row[&#39;data&#39;];
     
  }
   
  public function write($session_id, $session_data) {
    if(empty($session_id)) return null;
     
    $newExpires = time() + $this->maxlifetime;
    $sql = &#39;REPLACE INTO `%s` SET `session_id` = "%s", `session_data` = "%s", `session_expires` = "%u"&#39;;
    $sql = sprintf($sql, 
    mysqli_real_escape_string($this->link, $this->config[&#39;table&#39;]), 
    mysqli_real_escape_string($this->link, $session_id),
    mysqli_real_escape_string($this->link, $session_data),
    $newExpires);
     
    $result = mysqli_query($this->link, $sql);
    return mysqli_affected_rows($this->link);
     
  }
   
  public function destroy($session_id) {
    $sql = &#39;DELETE FROM `%s` WHERE `session_id` = "%s"&#39;;
    $sql = sprintf($sql, 
    mysqli_real_escape_string($this->link, $this->config[&#39;table&#39;]), 
    mysqli_real_escape_string($this->link, $session_id));
 
    $result = mysqli_query($this->link, $sql);
    return mysqli_affected_rows($this->link);
  }
   
  public function gc() {
    $sql = &#39;DELETE FROM `%s` WHERE `session_expires` < "%u"&#39;;
    $sql = sprintf($sql, 
    mysqli_real_escape_string($this->link, $this->config[&#39;table&#39;]), 
    time());
     
    $result = mysqli_query($this->link, $sql);
    return mysqli_affected_rows($this->link);
  }
   
}
 
class session {
 
  public static $collection = null;
   
  public static function open($clean = false, $token = false) {
    if($clean) ob_end_clean();
    if($token) session_id($token);
    session_start();
    self::$collection = $_SESSION;
  }
   
  public static function id() {
    $num_args = func_num_args();
    if($num_args) {
      $args = func_get_arg(0);
      return session_id($args);
    }else{
      return session_id();
    }
  }
   
  public static function get($name) {
    return isset($_SESSION[$name]) ? $_SESSION[$name] : null;
  }
   
  public static function set($name, $value) {
    $_SESSION[$name] = $value;
    return true;
  }
   
  public static function delete($name) {
    if(!isset($_SESSION[$name])) return null;
    unset($_SESSION[$name]);
    return true;
  }
   
  public static function destroy() {
    session_destroy();
  }
   
}
 
 
 
$config = array(
"host"=> "127.0.0.1",
"user"=> "root",
"password"=> "123456",
"database"=> "test",
"charset"=> "utf8",
"table"=> "user_session");
 
session_handler::init($config);
session::open();
session::set("profile", array("id"=> 1, "user"=> "haowei", "vip-level"=> 6));