This chapter covers the basics of the CI development framework and its usage by reviewing some fundamental web application examples. We will start with a basic hello world example and move to an interactive contact-form integration with a database. We will construct the CI applications by following a step-by-step method. Throughout this chapter, we need to remember that the CI development framework is an MVC-based development architecture (for more information, refer to the Wikipedia definition at http://en.wikipedia.org/wiki/Model-view-controller).

This chapter will primarily focus on the following topics:

By reviewing these examples, we will get the basics of using CI resources. We will begin by briefly reviewing the CI resources used. Then we will review a web application code that loads a static view page. Next we will use the model to retrieve data from a database and show it in a view. Finally, we'll add a view with a contact form to enter input and save it by calling a controller method into the database.