如何从一个管理员管理两个域

I am creating a booking engine . Same code will be used on two different domain BUT there should be an identifier to tell which domain will be using which code . Say in database I Identify AAA.COM should use code instance A and BBB.COM should use code instance B .

Both the domains are on same server .

Can anyone suggest how do I do that via apache or any tips to accomplish which I am looking for .

Well, php does have access to the HOST header being part of the request. Just use $_SERVER['SERVER_NAME'] or $_SERVER['HTTP_HOST']. Check the documentation for the difference: http://php.net/manual/en/reserved.variables.server.php

Using that you can create a condition inside your php scripts:

<?php
// ...
switch ($_SERVER['SERVER_NAME']) {
    case 'aaa.com': 
        // use database A
        break;
    case 'bbb.com': 
        // use database B
        break;
    default: 
        throw new Exception('undefined host at runtime');
}
// ...