var $map = array(
	'example.localhost'	=>	'local',
	'dev.example.com'	=>	'dev',
	'test.example.com'	=>	'test',
	'example.com'		=>	'live'
);

And intstead of your constructor write own:

function __construct() {
	$this->default = $this->{$this->map[$_SERVER['SERVER_NAME']]};
}

So, it is unneeded to change code in constructor, also for me it’s very usefull to place dev/test servers on subdomains.

Thank you!

I made a couple of additions, to support my situation of having the dev server running on a high port, not the standard port 80, and to also accommodate my work style, which includes local and public dev servers in addition to the client’s live/production server.

#automatically switch database configuration based on calling server
switch(strtolower($_SERVER['SERVER_NAME'].'_'.$_SERVER['SERVER_PORT']) {
        case 'localhost_1080':
        case '127.0.0.1_1080':
                $this->default = $this->local_cfg;
                break;
        case 'publicexample.net_80':
        case 'www.publicexample.net_80':
                $this->default = $this->pub_cfg;
                break;
        case 'live.com_80':
        case 'www.live.com_80':
                $this->default = $this->live_cfg;
                break;
        default:
                $this->default = $this->local;
}

BTW, I also use this same type of switch/case in the core.php, so as to set DEBUG to 0 on the live server, 1 on the public dev server, and 2 or 3 on the local dev server.