SESSION存放在数据库用法实例

本文实例讲述了SESSION存放在数据库用法。分享给大家供大家参考。具体如下：

<?php
/*
CREATE TABLE `ws_sessions` (
`session_id` varchar(255) binary NOT NULL default '',
`session_expires` int(10) unsigned NOT NULL default '0',
`session_data` text,
PRIMARY KEY (`session_id`)
) TYPE=InnoDB;
*/
class session {
// session-lifetime
var $lifeTime;
// mysql-handle
var $dbHandle;
function open($savePath, $sessName) {
// get session-lifetime
$this->lifeTime = get_cfg_var("session.gc_maxlifetime");
// open database-connection
$dbHandle = @mysql_connect("localhost","root","");
$dbSel = @mysql_select_db("test",$dbHandle);
// return success
if(!$dbHandle || !$dbSel)
 return false;
$this->dbHandle = $dbHandle;
return true;
}
function close() {
$this->gc(ini_get('session.gc_maxlifetime'));
// close database-connection
return @mysql_close($this->dbHandle);
}
function read($sessID) {
// fetch session-data
$res = mysql_query("SELECT session_data AS d FROM ws_sessions
   WHERE session_id = '$sessID'
   AND session_expires > ".time(),$this->dbHandle);
// return data or an empty string at failure
if($row = mysql_fetch_assoc($res))
 return $row['d'];
return "";
}
function write($sessID,$sessData) {
// new session-expire-time
$newExp = time() + $this->lifeTime;
// is a session with this id in the database?
$res = mysql_query("SELECT * FROM ws_sessions
   WHERE session_id = '$sessID'",$this->dbHandle);
// if yes,
if(mysql_num_rows($res)) {
 // ...update session-data
 mysql_query("UPDATE ws_sessions
   SET session_expires = '$newExp',
   session_data = '$sessData'
   WHERE session_id = '$sessID'",$this->dbHandle);
 // if something happened, return true
 if(mysql_affected_rows($this->dbHandle))
 return true;
}
// if no session-data was found,
else {
 // create a new row
 mysql_query("INSERT INTO ws_sessions (
   session_id,
   session_expires,
   session_data)
   VALUES(
   '$sessID',
   '$newExp',
   '$sessData')",$this->dbHandle);
 // if row was created, return true
 if(mysql_affected_rows($this->dbHandle))
 return true;
}
// an unknown error occured
return false;
}
function destroy($sessID) {
// delete session-data
mysql_query("DELETE FROM ws_sessions WHERE session_id = '$sessID'",$this->dbHandle);
// if session was deleted, return true,
if(mysql_affected_rows($this->dbHandle))
 return true;
// ...else return false
return false;
}
function gc($sessMaxLifeTime) {
// delete old sessions
mysql_query("DELETE FROM ws_sessions WHERE session_expires < ".time(),$this->dbHandle);
// return affected rows
return mysql_affected_rows($this->dbHandle);
}
}
$session = new session();
session_set_save_handler(array(&$session,"open"),
   array(&$session,"close"),
   array(&$session,"read"),
   array(&$session,"write"),
   array(&$session,"destroy"),
   array(&$session,"gc"));
session_start();
// etc...
?>

希望本文所述对大家的php程序设计有所帮助。