小编B.B*_*ing的帖子

我有这个类mysql使用php/ 连接到数据库mysqli:

class AuthDB {
    private $_db;

    public function __construct() {
        $this->_db = new mysqli(DB_SERVER, DB_USER, DB_PASS, DB_NAME)
        or die("Problem connect to db. Error: ". mysqli_error());
    }

    public function __destruct() {
        $this->_db->close();
        unset($this->_db);
    }
}

现在,我有列表用户的任何页面:

require_once 'classes/AuthDB.class.php';

session_start();

$this->_db = new AuthDB(); // error For This LINE
$query = "SELECT Id, user_salt, password, is_active, is_verified FROM Users where email = ?";
$stmt = $this->_db->prepare($query);

        //bind parameters
        $stmt->bind_param("s", $email);

        //execute statements
        if ($stmt->execute()) { …

我需要require_once这个文件main.class.php,并functions.php和config.php到admin/test.php.如何找到php需要真正的路径？!

注:main.class.php在class folder,functions.php在includes folder和config.php在root目录test.php中admin folder.

文件目录:

root
    /admin/
        ->test.php 
    /class/
        ->main.class.php
    /includes/
        ->functions.php
    /templates
    config.php
    phpinfo.php