How PHP saves session sessions using MySQL _php tips

The example in this article describes how PHP saves session sessions using MySQL. Share to everyone for your reference. The specific analysis is as follows:

In many large systems generally have this function, but to separate the analysis, the online reliable information is not too much here I organized an issue to share with you

Saving session sessions with MySQL has many advantages over files:

1 in favor of distributed systems, files can only be stored on a single machine
2 for large access to the system, the use of files each session saved in a file, the directory will be super large, find session files will be more difficult.

To save a session using MySQL first, you will create a table of sessions: <?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". $data _name. "'"; If it is exist if ($rs _table=mysql_query ($sql, $login)) {if ($rs _value=mysql_fetch_array ($rs _table)) {echo database already exists ！
  \n! "; 
 Exit ();  
}} $sql = "CREATE DATABASE $data _name"; mysql_query ($sql); Crate DB Echo database created successfully! 
\ n ";
mysql_select_db ($data _name, $login); $sql = "CREATE TABLE ' Sessions ' (' sessionkey ' varchar ') NOT NULL default ', ' Sessionarray ' blob not null, ' Sessionexp Time ' int ' unsigned not NULL default ' 0 ', PRIMARY key (' SessionKey '), key ' SessionKey ' (' SessionKey ') Engine=myisa M DEFAULT Charset=utf8 ";
New Database SQL statement mysql_query ($SQL); Echo succeeded in creating a new database table!
 ";?>

The Mysqlsession class is as follows: <?php class Mysqlsession {//Note the page with session usage.
Page must be below, the beginning of the page can not be left blank. Private $DB _server = "localhost"; Database server host name private $DB _name = "";  Database name private $DB _user = "root";  MYSQL database access User name private $DB _pass = ""; 
MYSQL database access password private $DB _select_db = "";  Private $SESS _life = 1440;
Maximum length of session, per second.
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_r
 EAD '), Array (& $this, ' Sess_write '), Array (& $this, ' Sess_destroy '), Array (& $this, ' sess_gc '));
Session_Start (); function Sess_open ($save _path, $session _name) {//Open database connection if (! $this->db_select_db = mysql_pconnect ($this->db_s 
Erver, $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 $this->db_name "; 
 Die 
return true; 
function Sess_close () {return true; The function Sess_read ($SessionKey) {$Query = "Select Sessionarray from sessions WHERE SessionKey = '". $SessionKey. "' and Sessionexptime > ".
  Time ();
  Expired does not read. 
 $Result = mysql_query ($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; 
 Update session expiration,//session expiration = Last Update time + Session maximum usage length $SessionArray = addslashes ($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 $Result; 
 The function Sess_destroy ($SessionKey) {$Query = "DELETE from sessions WHERE SessionKey = '". $SessionKey. "'"; 
 $Result = mysql_query ($Query, $this->db_select_db); 
return $Result;
The function sess_gc ($maxlifetime) {//This garbage scavenger system call. The default is 1440 seconds to clear once.
 Parameters can be set inside the php.ini. $Query = "DELETE from sessions WHERE Sessionexptime <". 
 Time (); 
 $Result = mysql_query ($Query, $this->db_select_db); 
Return Mysql_affected_rows ($this->db_select_db);

 ?>//Usage: In the original use of Session_Start place, replace with $session = new mysqlsession ()//Note: To open the database before the program is included, the main program cannot close the database before exiting, otherwise it will be wrong.

I hope this article will help you with your PHP programming.