How to operate session and database in php

<?php

$hostname_login = "localhost"; // Server address

$username_login = "root"; // User name

$password_login = ""; // Password

//

$data_name = "session"; // Database name

$login = mysql_pconnect($hostname_login, $username_login, $password_login) or trigger_error(mysql_error(),E_USER_ERROR);

$sql="SHOW DATABASES LIKE '".$data_name."'"; // If it is exist

if($rs_table=mysql_query($sql,$login)) {

  if($rs_value=mysql_fetch_array($rs_table)) {

   echo "数据库已经存在！\n!";

   exit();

  }

}

$sql="CREATE DATABASE $data_name";  

mysql_query($sql); // Crate database

echo "数据库创建成功！\n";

mysql_select_db($data_name, $login);

$sql="CREATE TABLE `sessions` (

`SessionKey` varchar(32) NOT NULL default '',

`SessionArray` blob NOT NULL,

`SessionExpTime` int(20) unsigned NOT NULL default '0',

PRIMARY KEY (`SessionKey`),

KEY `SessionKey` (`SessionKey`)

) ENGINE=MyISAM DEFAULT CHARSET=utf8"; //新建数据库 sql语句

mysql_query($sql);

echo "成功新建数据库表！";

?>

<?php 

class MysqlSession {

// 注意在有使用Session的页面。页面一定要顶格，页面开始处不能留空。

private $DB_SERVER = "localhost"; // 数据库服务器主机名

  private $DB_NAME = ""; // 数据库名字

  private $DB_USER = "root"; // MYSQL 数据库访问用户名

  private $DB_PASS = ""; // MYSQL 数据库访问密码

  private $DB_SELECT_DB = "";

//private $SESS_LIFE = 1440; // Session的最大使用时长，单位秒。

private $SESS_LIFE = 0;

function MysqlSession (&$sessionDB) {

  //session_write_close();

  $this->DB_NAME = &$sessionDB;

  $this->SESS_LIFE = get_cfg_var("session.gc_maxlifetime");

  session_module_name('user');

  session_set_save_handler(

  array(&$this, 'sess_open'),

  array(&$this, 'sess_close'),

  array(&$this, 'sess_read'),

  array(&$this, 'sess_write'),

  array(&$this, 'sess_destroy'),

  array(&$this, 'sess_gc')

  );

  session_start();

}

function sess_open($save_path, $session_name){  // 打开数据库连接

  if (! $this->DB_SELECT_DB = mysql_pconnect($this->DB_SERVER, $this->DB_USER, $this->DB_PASS)) {

  echo "SORRY! MYSQL ERROR : Can't connect to $this->DB_SERVER as $DB_USER";

  echo "MySQL Error: ", mysql_error();

  die;

  }

  if (! mysql_select_db($this->DB_NAME, $this->DB_SELECT_DB)) {

  echo "SORRY! MYSQL ERROR : Unable to select database $this->DB_NAME";

  die;

  }

  return true;

}

function sess_close() {

    return true;

}

function sess_read($SessionKey){ 

    $Query = "SELECT SessionArray FROM sessions WHERE SessionKey = '".$SessionKey."' AND SessionExpTime > " . time();

    // 过期不读取。

    $Result = mysql_query($Query, $this->DB_SELECT_DB);

  if (list($SessionArray) = mysql_fetch_row($Result)) {

     return $SessionArray;

  }

  return false;

}

function sess_write($SessionKey, $VArray) {

  $SessionExpTime = time() + $this->SESS_LIFE;

  // 更新Session过期时间，Session过期时间 = 最后一次更新时间 + Session的最大使用时长

  $SessionArray = addslashes($VArray);

  $Query = "INSERT INTO sessions (SessionKey,SessionExpTime,SessionArray) VALUES ('".$SessionKey."','".$SessionExpTime."','".$SessionArray."')";

  $Result = mysql_query($Query, $this->DB_SELECT_DB);

  if (!$Result){

      $Query = "UPDATE sessions SET SessionExpTime = '".$SessionExpTime."', SessionArray = '".$SessionArray."' WHERE SessionKey = '".$SessionKey."' AND  SessionExpTime > " . time();

      $Result = mysql_query($Query, $this->DB_SELECT_DB);

  } 

  return $Result;

}

function sess_destroy($SessionKey) {

  $Query = "DELETE FROM sessions WHERE SessionKey = '".$SessionKey."'";

  $Result = mysql_query($Query, $this->DB_SELECT_DB);

  return $Result;

}

function sess_gc($maxlifetime) {

// 这个垃圾清除器系统调用。默认是1440秒清除一次。

//参数可以在PHP.ini里面设置。

  $Query = "DELETE FROM sessions WHERE SessionExpTime < " . time();

  $Result = mysql_query($Query, $this->DB_SELECT_DB);

  return mysql_affected_rows($this->DB_SELECT_DB);

}

}

?>