Introduction to CodeIgniter and How to install codeigniter

CodeIgniter (CI) is one of popular php framework. If you are already building PHP Application, CodeIgniter will help you to do it better and more easily. With CodeIgniter, you can save time, make your web more robust, your code will be easier to read and maintenance. It is free, lightweight, and simple to install. In this post, we will know more deep about CodeIgniter before write code.

Nice, CodeIgniter is small and lightweight framework. You don’t need long time to download it. You can get it from http://www.codeigniter.com. CI was written by Rick Ellis, rock musician turned programmer.

With CodeIgniter, you can cut down the amount of code you need to type. This is not just good for lazy, but: less type, fewer mistake, and less time for spend debugging.
But, CodeIgniter is not everything. We will not find ‘engine generator’ that can build page self. Several frameworks have features like that. For example, they can create web page (that to do basic Create, Read, Update, and Delete operation) automatically. CodeIgniter doesn’t do this.

This, I copy from their help page: “Our goal for CodeIgniter is maximum performance, capability, and flexibility in the smallest, lightest possible package.
From a technical and architectural standpoint, CodeIgniter was created with the following objectives:

• Dynamic Instantiation. In CodeIgniter, components are loaded and routines executed only when requested, rather than globally. No assumptions are made by the system regarding what may be needed beyond the minimal core resources, so the system is very light-weight by default. The events, as triggered by the HTTP request, and the controllers and views you design will determine what is invoked.

• Loose Coupling. Coupling is the degree to which components of a system rely on each other. The fewer components depend on each other the more reusable and flexible the system becomes. Our goal was a very loosely coupled system.

• Component Singularity. Singularity is the degree to which components have a narrowly focused purpose. In CodeIgniter, each class and its functions are highly autonomous in order to allow maximum usefulness.

Nice feature, CodeIgniter is very flexible. We can apply at PHP 4.3.2 and above, or PHP 5.0 or above. CI support serveral database: MySQL, MySQLi, MS SQL, Postgre, Oracle, SQLite, and ODBC.

Ok, now, we will learn how to install CodeIgniter.
For this series i’ll be using the latest version of CodeIgniter at the time of writing, The latest is Version 3.0rc3

Installation
1. Head over to the CodeIgniter website http://codeigniter.com/ and download the source.
2. Extract the CodeIgniter files into an appropriate folder on your web server. if you want to work locally, use WAMP, MAMP or XAMPP.
3. Open your installation in a web browser and you should get the screen below.