Top Most Codeigniter Interview Questions and Answers

Codeigniter (CI) is an open-source framework for web application. It is used to develop websites on PHP. It is loosely based on the popular model–view–controller (MVC) development pattern, and it is easy to use compare to other PHP frameworks. The first public version of CodeIgniter was released by EllisLab on February 28, 2006.

Question 1: What are the features of Codeigniter?

Codeigniter is free to use,its an open source framework.
Model View Controller Based System.
Extremely Light Weight.
Full Featured database classes with support for several platforms.
CodeIgniter is Extensible.The system can be easily extended through the use of your own libraries, helpers, or through class extensions or system hooks.
Full Featured database classes with support for several platforms,Security and XSS Filtering,Error Logging.

Question 2: Explain Codeigniter File Structure?

following are the folder structure :

application

cache
Config
Controllers
core
errors
helpers
hooks
language
libraries
logs
models
third-party
views

system

core
database
fonts
helpers
language
libraries

assets

css
images
js

Question 3: Explain what are hooks in CodeIgniter?

Codeigniter’s hooks feature provides a way to change the inner working of the framework without hacking the core files. In other words, hooks allow you to execute a script with a particular path within the Codeigniter. Usually, it is defined in application/config/hooks.php file.

<?php
$hook['pre_controller'] = array(
'class' => 'MyClass',
'function' => 'Myfunction',
'filename' => 'Myclass.php',
'filepath' => 'hooks',
'params' => array('param1', 'param2', 'param3')
);
?>

<?php

$hook['pre_controller'] = array(

'class' => 'MyClass',

'function' => 'Myfunction',

'filename' => 'Myclass.php',

'filepath' => 'hooks',

'params' => array('param1', 'param2', 'param3')

);

Question 4: How to load model in CodeIgniter?

Within your controller functions, models will typically be loaded; you will use the function

  <?php $this->load->model (‘Model_Name’);?>

1	<?php $this->load->model (‘Model_Name’);?>

Question 5: Explain what helpers in CodeIgniter are and how you can load a helper file?

In CodeIgniter, helpers are group of function in a particular category that assist you to perform specific functions. In CodeIgniter, you will find many helpers like URL helpers- helping in creating links, Text Helpers- perform various text formatting routines, Cookies- helpers set and read cookies. You can load a helper file by using the command:

  <?php $this->load->helper (‘helper-name’); ?>

1	<?php $this->load->helper (‘helper-name’); ?>

Question 6: Explain routing in Codeigniter?

In CodeIgniter, the way PHP files served is different rather than accessing it directly from the browser. This process is called routing. Routing in CodeIgniter gives you the freedom to customize the default URL pattern to use our own URL pattern according to the requirement. So, whenever there is a request made and matches our URL pattern it will automatically direct to the specified controller and function.