How to save session in php using MySQL

The example in this article describes how PHP uses MySQL to save the session. Share it with everyone for your reference. The specific analysis is as follows:

This function is generally available in many large systems, but it needs to be separated and analyzed. There is not much information on the Internet. Here I compiled an article to share with you.

It is more convenient to use MySQL to save sessions. Files have many advantages:

1) Conducive to distributed systems, files can only be saved on one machine
2) Conducive to systems with large access volume, when using files, each session is saved in a file, and the directory will be super If it is large, it will be more difficult to find the session file.

To use MySQL to save a session, you must first create the session table:

<?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); 
$sql="SHOW DATABASES LIKE &#39;".$data_name."&#39;"; // 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);
$sql="CREATE TABLE `sessions` ( 
`SessionKey` varchar(32) NOT NULL default &#39;&#39;, 
`SessionArray` blob NOT NULL, 
`SessionExpTime` int(20) unsigned NOT NULL default &#39;0&#39;, 
PRIMARY KEY (`SessionKey`), 
KEY `SessionKey` (`SessionKey`) 
) ENGINE=MyISAM DEFAULT CHARSET=utf8"; //新建数据库 sql语句
mysql_query($sql);
echo "成功新建数据库表！";
?>

MysqlSession class is as follows:

<?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;
  $this->SESS_LIFE = get_cfg_var("session.gc_maxlifetime");
  session_module_name(&#39;user&#39;);
  session_set_save_handler( 
  array(&$this, &#39;sess_open&#39;), 
  array(&$this, &#39;sess_close&#39;), 
  array(&$this, &#39;sess_read&#39;), 
  array(&$this, &#39;sess_write&#39;), 
  array(&$this, &#39;sess_destroy&#39;), 
  array(&$this, &#39;sess_gc&#39;) 
  );
  session_start();
}
function sess_open($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&#39;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){  
    $Query = "SELECT SessionArray FROM sessions WHERE SessionKey = &#39;".$SessionKey."&#39; 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); 
  $Query = "INSERT INTO sessions (SessionKey,SessionExpTime,SessionArray) VALUES (&#39;".$SessionKey."&#39;,&#39;".$SessionExpTime."&#39;,&#39;".$SessionArray."&#39;)"; 
  $Result = mysql_query($Query, $this->DB_SELECT_DB); 
  if (!$Result){ 
      $Query = "UPDATE sessions SET SessionExpTime = &#39;".$SessionExpTime."&#39;, SessionArray = &#39;".$SessionArray."&#39; WHERE SessionKey = &#39;".$SessionKey."&#39; AND  SessionExpTime > " . time(); 
      $Result = mysql_query($Query, $this->DB_SELECT_DB); 
  }  
  return $Result; 
} 
function sess_destroy($SessionKey) { 
  $Query = "DELETE FROM sessions WHERE SessionKey = &#39;".$SessionKey."&#39;"; 
  $Result = mysql_query($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); 
} 
}
?>

Usage: Where session_start was originally used, replace it with $session = new MysqlSession ()

Note: Open this program before including it Database, the database cannot be closed before the main program exits, otherwise an error will occur.

I hope this article will be helpful to everyone’s PHP programming design.

For more articles on how PHP uses MySQL to save sessions, please pay attention to the PHP Chinese website!