Implementing MVC in PHP: The Model

by Joe Stump

This article series (starting with Understanding MVC in PHP and continued in Implementing MVC in PHP: The Controller and Implementing MVC in PHP: The View) demonstrates how to build an MVC web framework using PHP 5. This article explains the Model part of Model-View-Controller design.

Click here to find out more!

The Model is where the majority of the application’s logic sits. It is where you run queries against the database and perform calculations on input. A good example of what a Model would look like is a simple login script. The login script gets user input from a form, validates it against the database, and then logs in the user.

The first application using the newly created framework will be the users module. I will be creating three Models:

  • login.php validates input from a form against the database
  • logout.php logs a user out and destroys the associated session
  • whoami.php displays simple user information, similar to the Unix program of the same name

Because I am introducing the idea of sessions and users into the framework, I will need to create a few more foundation classes as well as a table in a database. Before I go over the code of login.php, I’d like to walk through these classes.


FR_Session is a wrapper for the built-in PHP sessions. The code isn’t very involved and provides only basic support for starting, destroying, and writing sessions.