我正在为某人排除网站故障，其中一个错误如下：
Constant serverusername already defined in C:'xampp'htdocs'employee'inc'db.php on line 5
db.php的内容如下：
<?php
//Database Connection Settings
define ('hostnameorservername','localhost'); //Your server name or hostname goes in here
define ('serverusername','root'); //Your database username goes in here
define ('serverpassword',''); //Your database password goes in here
define ('databasenamed','asset'); //Your database name goes in here
global $connection;
$connection = @mysql_connect(hostnameorservername,serverusername,serverpassword) or die('Connection could not be made to the SQL Server. Please report this system error at <font color="blue">info@servername.com</font>');
@mysql_select_db(databasenamed,$connection) or die('Connection could not be made to the database. Please report this system error at <font color="blue">info@servername.com</font>');
?>
当我在整个目录上搜索"serverusername"时，除了在上，我在其他任何地方都找不到它
:'xampp'htdocs'employee'inc'db.php on line 5
然而，线路：
include 'inc/db.php';
存在于许多文件中。
问题出在哪里？我该如何解决？提前感谢
此问题可能是由于在同一页面上多次包含db.php文件而导致的。
试试这个：
include_once 'inc/db.php';
用以下代码替换您的代码：
defined('hostnameorservername') or define('hostnameorservername', 'localhost');
defined('serverusername') or define('serverusername', 'root');
defined('serverpassword') or define('serverpassword', '');
defined('databasenamed') or define('databasenamed', 'asset');