使用Mysql数据库保存session会话优点如下：
1)有利用分布式系统的开发，实现单一登录等；files只能保存在一台服务器上
2)有利用大量用户访问该系统而不会导致数据缓存庞大，使用files方式每个session保存在一个文件中目录会相当的庞大并且查找session文件十分的困难。
通过php访问mysql数据创建session会话表存储会话记录，具体代码操作如下：
<?php
$DB_SERVER = "localhost"; // 数据库访问地址
$DB_USER = "root"; // 登录用户名
$DB_PASS = ""; // 密码
$DB_NAME = "session"; // 数据库名称
$login = mysql_pconnect($DB_SERVER, $DB_USER, $DB_PASS) or trigger_error(mysql_error(),E_USER_ERROR);
$sql="SHOW DATABASES LIKE '".$DB_NAME."'";
if($rs_table=mysql_query($sql,$login)) {
if($rs_value=mysql_fetch_array($rs_table)) {
echo "数据库已经存在!";
exit();
}
}
$sql="CREATE DATABASE $DB_NAME";
mysql_query($sql);
echo "数据库创建成功！\n";
mysql_select_db($DB_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！";
?>针对session会话表进行相关的增删改查操作类，具体代码如下：
<?php
class MysqlSession {
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 = 1550; // 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){
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1550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);
}
}
?>
