"If you plan to ship your PHP application for use by another person or company, you need to make it configurable. At the very least, you want to allow the user to set the database login and password in a way that is secure so that material isn't externally visible.
"This article shows several techniques for storing configuration settings and editing them. In addition, it provides some guidance for what elements to make configurable and how to avoid the traps of building too much or too little configurability..."
