CodeIgniter is an open-source software rapid development web framework, for use in building dynamic web sites with PHP. CodeIgniter is loosely based on the popular model–view–controller (MVC) development pattern. While controller classes are a necessary part of development under CodeIgniter, models and views are optional. Codeigniter can be also modified to use Hierarchical Model View Controller which allows developers to maintain modular grouping of Controller, Models and View arranged in a sub-directory format.

MVC structure of Codeigniter:

Model: Basically data is represented by model and all its functions retrieve, insert and restructure the database information as model contains data logic and also represents classes, data structures etc. Despite the fact of data validation, validation class validates the data by defining the validating object with a few assigned rules and certain error messages that have been programmed.

In case of data sent by URL, automatic validation procedure has been provided by validation object. View: is the information- in general a web page which is accessible to users. Just like a header or footer, we can say a page scrap in Code Igniter, which can either be RSS page or any page. Controller: is just a name of a class file linked with a URI and it is loaded by Code Igniter. But, for loading purpose not only matching of controller's name with first segment of Url is necessary, but also first character of class name is required in upper case. Here, the parent controller class is extended and all its functions are inherited by controller class. Function of controller, need to call is determined by second segment of the URL as it loads "index" function when clears.

Benefits of CodeIgniter:

• A small track and astounding presentation
• Provision of broad compatibility along with standard hosting accounts,
• Configuration and normal coding rules are not required
• Depiction of straightforward solutions
• Free from complex structures and development
• It's built on a linear, easy-to-use folder structure.

• It's open source and simple to configure and customize for your own needs.
• You can construct your own cleaner URI lines in CodeIgniter.