将session存储到数据库中

CREATE TABLE sessions (  
  id CHAR(32) NOT NULL,  
  data TEXT,  
  last_accessed TIMESTAMP NOT NULL,  
  PRIMARY KEY (id)  
);

<?php  
/**  
 * Created by PhpStorm.  
 * User: michaeldu  
 * Date: 15/7/14  
 * Time: 下午2:57  
 */  
$sdbc = NULL;  
  
function open_session() {  
    global $sdbc;  
    $sdbc = mysqli_connect('192.168.31.172', 'root', 'root', 'phpadvanced');  
    return true;  
}  
  
function close_session() {  
    global $sdbc;  
    return mysqli_close($sdbc);  
}  
  
function read_session($sid) {  
    global $sdbc;  
    $q = sprintf('SELECT data FROM sessions WHERE  id="%s"', mysqli_real_escape_string($sdbc, $sid));  
    $r = mysqli_query($sdbc, $q);  
  
    if (mysqli_num_rows($r) == 1) {  
        list($data) = mysqli_fetch_array($r, MYSQLI_NUM);  
        return $data;  
    } else {  
        return '';  
    }  
}  
  
function write_session($sid, $data) {  
    global $sdbc;  
  
    $q = sprintf('REPLACE INTO sessions (id, data) VALUES ("%s", "%s")', mysqli_real_escape_string($sdbc, $sid), mysqli_real_escape_string($sdbc, $data));  
    $r = mysqli_query($sdbc, $q);  
    return true;  
}  
  
function destroy_session($sid) {  
    global $sdbc;  
    $q = sprintf('DELETE FROM session WHERE id="%s"', mysqli_real_escape_string($sdbc, $sid));  
    $r = mysqli_query($sdbc, $q);  
  
    $_SESSION = array();  
  
    return true;  
}  
  
function clean_session($expire) {  
    global $sdbc;  
  
    $q = sprintf('DELETE FROM sessions WHERE DATE_ADD(last_accessed, INTERVAL %d SECOND) < NOW()', (int)$expire);  
    $r = mysqli_query($sdbc, $q);  
  
    return true;  
}  
  
session_set_save_handler('open_session', 'close_session', 'read_session', 'write_session', 'destroy_session', 'clean_session');  
  
session_start();

  
    
    
    colour_blue  
      
      
      
        
    
<?php  
if(empty($_SESSION)) {  
    $_SESSION['blah'] = 'umlaut';  
    $_SESSION['this'] = 3615684.45;  
    $_SESSION['that'] = 'blue';  
    echo 'Session已存储';  
} else {  
    echo 'SESSION已存在, '.print_r($_SESSION, 1).'';  
}  
  
if(isset($_GET['logout'])) {  
    session_destroy();  
    echo '会话结束';  
} else {  
    echo '登出';  
}  
  
echo '会话数据: '.print_r($_SESSION, 1).'';  
?>