CodeIgniter Interview Questions and Answers

It is a PHP open-source web development framework which is used for building dynamic websites.

4.0 is the latest version of the Codelgniter framework. This version is released on September 3, 2019.

Here are some new features that support Codelgniter

• URL Helper
• Query builder
• Email Library
• Form Validation Library
• Session Library

Codelgniter updated these modules to enhance features.

Currently Codeigniter supports these databases that's are given below :-

• MySQL
• Oracle
• PostgreSQL
• SQLite
• ODBC
• Firebird etc

It is a type of events which can be called before and after the execution of a program in CodeIgniter. For example Hooks can be used where we need to check whether a user is logged in or logged out before the execution of controller.

It can be globally enabled or disabled by setting in the application/config/config.php page

It can be defined in application/config/hooks.php page. In CodeIgniter each hook is specified like an array with this prototype:

You can do it with this $this->load->model("ModelName");

You can use this $this->load->view('name'); to load a view in CodeIgniter.

In CodeIgniter when a specified file in the default controller loaded by default when there is no file name mentioned in URL. By default "welcome.php" file is loaded after installing CodeIgniter.

Yes, we can change it from application/config/routes.php. We have to pass our controller name which we want to load by default in $route['default_controller']

For example, now the frontend is the default controller $route['default_controller'] = 'Frontend'; from now. Interview questions on Codeigniter are always a level up and thus a little tough to crack.

The basic URL structure is bestinterviewquestion.com/class/function/ID.

Here class represents controller's class that needs to be invoked.
Here "function" is name of method which is called.
ID is an additional parameter that is passed to controllers.

Helpers is collection of functions which help us with different tasks as name suggested. Every helper function is used to performs specific task with no dependence on other functions.

CodeIgniter provide various types of helper class like url_helper, captcha_helper ,email_helper. All these helpers are located in system/helper.

By default CodeIgniter does not load any Helper files. First step is to be load Helper. After loaded it is available in all controller and views.

How we can load a Helper : $this->load->helper('name');
Here "name" is file name of helper.

How to load multiple Helpers at one time.
$this->load->helper(array('helper1', 'helper2', 'helper3')); // Here helper1,helper2,helper3 are different helper's name.

Helper is a set of Common functions which we can use within Models, Views, Controllers everywhere. Once we include that file then we can get access to the functions.
Library is a class which we need to make an instance of the class by $this->load->library() this function.

NOTE : A library is used in object-oriented context but a helper is more suitable to be used within the Views