What is CodeIgniter?

CodeIgniter is a powerful PHP framework used for developing web applications rapidly.

What are the key features of CodeIgniter?

CodeIgniter features include a small footprint, excellent documentation, a lightweight framework, and a rich set of libraries.

Explain MVC architecture in CodeIgniter.

MVC stands for Model-View-Controller. CodeIgniter follows this design pattern to separate application logic, presentation, and data handling.

How can you install CodeIgniter?

Download the CodeIgniter package, extract it to your server, and configure the config.php and .htaccess files.

What is routing in CodeIgniter?

Routing is the process of defining how URLs should be mapped to controllers and methods in CodeIgniter.

What is a Controller in CodeIgniter?

A controller in CodeIgniter is responsible for handling user requests and interacting with models and views to generate responses.

Explain the purpose of models in CodeIgniter?

Models in CodeIgniter handle database interactions, data validation, and business logic.

What is a View in CodeIgniter?

Views in CodeIgniter are responsible for rendering HTML output and displaying data to the user.

How do you load a model in CodeIgniter?

You can load a model using the $this->load->model('model_name'); method in a controller.

What is the role of the autoload.php file in CodeIgniter?

It allows you to specify which libraries, helpers, and models should be loaded automatically when the application starts.

Explain the purpose of the CodeIgniter database configuration file.

It contains database connection settings and is used to connect to the database in CodeIgniter.

How do you create a custom 404 error page in CodeIgniter?

You can create a custom 404 error page by editing the routes.php file in the application/config directory.

What is a CodeIgniter library?

Libraries are reusable code components in CodeIgniter that provide common functionality like form validation, session management, and email handling.

How do you load a CodeIgniter library?

You can load a library using $this->load->library('library_name'); in a controller.

Explain CodeIgniter helpers.

Helpers are sets of utility functions that can be loaded and used throughout your application.

What is the purpose of CodeIgniter's URL helper?

It provides functions to generate URLs and manage URL-related tasks.

How do you handle form validation in CodeIgniter?

You can use the form_validation library and set validation rules in your controllers.

What is the purpose of CodeIgniter's session library?

It allows you to store and retrieve session data in your application.

How do you set and retrieve session data in CodeIgniter?

You can set session data using $this->session->set_userdata('key', 'value'); and retrieve it using $this->session->userdata('key');.

What are hooks in CodeIgniter?

Hooks are specific points in the CodeIgniter execution where you can tap into and modify the behavior of the core system.

How do you enable and configure hooks in CodeIgniter?

You can enable hooks by editing the config.php file and configure them in the hooks.php file.

What is the purpose of the config.php file in CodeIgniter?

It contains various configuration settings for your CodeIgniter application.

Explain the concept of routes in CodeIgniter.

Routes define how URLs are mapped to controllers and methods in CodeIgniter.

How do you pass data from a controller to a view in CodeIgniter?

You can use the $this->load->view('view_name', $data); method to pass data to a view.

What is CodeIgniter's database abstraction?

It provides a simple and consistent interface for interacting with different database systems.

How do you execute a raw SQL query in CodeIgniter?

You can use the $this->db->query('your_query'); method to execute raw SQL queries.

What is CodeIgniter's Active Record class?

It provides a more convenient and secure way to build and execute database queries.

How do you enable database profiling in CodeIgniter?

Set $this->db->enable_profiler(TRUE); in your controller to enable database query profiling.

What is CodeIgniter's form helper used for?

It provides functions to generate HTML form elements and simplify form handling.

Explain how CodeIgniter handles security.

CodeIgniter has built-in security features such as Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF) protection.

How do you enable CSRF protection in CodeIgniter?

You can enable CSRF protection in the config.php file by setting $config['csrf_protection'] to TRUE.

What is a callback function in CodeIgniter's form validation?

Callback functions are custom validation rules that you can define for form validation.

How do you handle file uploads in CodeIgniter?

You can use the upload library and configure it to handle file uploads.

What is CodeIgniter's caching system used for?

It allows you to cache the output of pages to improve performance.

How do you enable caching in CodeIgniter?

You can enable caching by setting $this->output->cache(n); in your controller, where n is the number of minutes to cache.

Explain the purpose of CodeIgniter's pagination library.

It simplifies the creation of paginated result sets.

How do you implement pagination in CodeIgniter?

You can use the pagination library to generate pagination links and limit database query results.

What is CodeIgniter's email library used for?

It simplifies sending email messages in CodeIgniter.

How do you send an email using CodeIgniter's email library?

Load the library, configure email settings, and use $this->email->send(); to send an email.

What is CodeIgniter's language class used for?

It allows you to manage language files and internationalization in your application.

Explain the purpose of CodeIgniter's encryption library.

It provides methods for encrypting and decrypting data securely.

How do you enable error logging in CodeIgniter?

You can enable error logging in the config.php file by setting $config['log_threshold'].

What is CodeIgniter's image manipulation library used for?

It enables you to resize, crop, and manipulate images easily.

How do you load the image manipulation library in CodeIgniter?

Use $this->load->library('image_lib'); to load the library.

Explain the purpose of CodeIgniter's CAPTCHA library.

It helps prevent automated form submissions by generating and validating CAPTCHA images.

How do you use CAPTCHA in CodeIgniter?

Load the CAPTCHA library, configure it, and use $this->captcha->create_captcha(); to generate a CAPTCHA image.

What is CodeIgniter's profiler used for?

It provides detailed information about the performance of your application's queries and execution.

How do you enable the profiler in CodeIgniter?

Set $this->output->enable_profiler(TRUE); in your controller.

What is CodeIgniter's security class used for?

It offers functions to help sanitize input data and protect against common security vulnerabilities.

How can you extend CodeIgniter's functionality with third-party libraries and plugins?

You can integrate third-party libraries and plugins by downloading them, placing them in the appropriate directories, and loading them when needed.