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。