Step 1 : Model View and Controller basics

The Controller serves as an intermediary between the Model, the View, and any other resources needed to process the HTTP request and generate a web page.
The Model represents your data structures. Typically your model classes will contain functions that help you retrieve, insert, and update information in your database.
The View is the information that is being presented to a user. A View will normally be a web page, but in CodeIgniter, a view can also be a page fragment like a header or footer. It can also be an RSS page, or any other type of “page”.