使用PHP在MySQL中的数据库连接问题

Issue Is with the database connection for an open source Project(PHP). Everything works fine apart from the database connection required for login. Following is the error that can be seen after login.

Warning: require_once(../mysqli_connect.php): failed to open stream: No such file or directory in /Applications/XAMPP/xamppfiles/htdocs/airline-ticket-reservation-system-master/login_handler.php on line 44

Fatal error: require_once(): Failed opening required '../mysqli_connect.php' (include_path='.:/Applications/XAMPP/xamppfiles/lib/php') in /Applications/XAMPP/xamppfiles/htdocs/airline-ticket-reservation-system-master/login_handler.php on line 44

mysqli_connect.php

<?php
DEFINE('DB_USER','Harry');
DEFINE('DB_PASSWORD','passpasshello');
DEFINE('DB_HOST','localhost');
DEFINE('DB_NAME','airline_reservation');

$dbc=mysqli_connect(DB_HOST,DB_USER,DB_PASSWORD,DB_NAME)
OR dies('Could not connect to MySQL:' .
    mysqli_connect_error());
?>

enter image description here

try to include the mysqli_connect file where the error occur

require_once(../MySql DatabaseConnection file/mysqli_connect.php)

reference