I am fairly new to the PHP framework scene. I have been using CodeIgniter for about 3-4 months and I have found it to be quite straightforward.  I have been able to develop websites quickly using an understandable structure.

When I first began defining constants with CodeIgniter, I used a method that I learned in the book, “Professional CodeIgniter
“. I placed all of my constants at the bottom of the config.php file (system/application/config/config.php).

$config['jquery_assets'] = 'assets/js/jquery/';

To access the configuration item in my application, I would write something like:

$this->plugin = base_url() . $this->config->item('jquery_assets') .'imgooglemaps/jquery.imGoogleMaps-0.5.js';

While this works fine, I really wanted to define constants in the traditional PHP way. I recently noticed a file named constants.php (system/application/config/constants.php). Here, I am able to define application constants like a traditional PHP application.

define("GAL_THUMB_MAX_W", 120);

I think that I will use the constants.php file from now on.