Cara Mengatasi ERROR notice: Constant DB_NAME already defined

<?php
     define('DB_HOST','******');
     define('DB_USER','******');
     define('DB_PASS','******');
     define('DB_NAME','******');  

    $cms_db = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME);

         if(!$cms_db){
          echo"Could not connect: ".mysql_error();
     } 
?>

<?php
   require('config.php');
   $perm = $_GET['p'];
   $query = "SELECT * FROM cms WHERE permalink = '$perm'";
   $result = $cms_db->query($query);
   $row = $result->fetch_assoc();
   $page_title = $perm;
   require('header.php');
?>
<h1><?=$row['title'];?></h1>
<hr/><br/>
<p class="para"><?=$row['content']?></p>

<?php require('footer.php');?>

Anda mungkin termasuk config.php beberapa kali. Periksa semua skrip Anda dan temukan duplikat ini. Anda bisa menggunakan require_once () daripada require () untuk mencegah hal ini.

SELAMAT MENCOBA !! GOOD LUCK