Codeigniter Interview Questions and Answers in 2025 (100+ Q&A)

Codeigniter

Ques:- How to write join query in codeigniter?

Asked In :-

Right Answer:
In CodeIgniter, you can write a join query using the Query Builder class like this:

```php
$this->db->select('table1.column1, table2.column2');
$this->db->from('table1');
$this->db->join('table2', 'table1.id = table2.foreign_id');
$query = $this->db->get();
$result = $query->result();
```

Codeigniter

Ques:- How to truncate table with query in codelgniter?

Asked In :-

Right Answer:
To truncate a table in CodeIgniter, you can use the following query:

```php
$this->db->query("TRUNCATE TABLE your_table_name");
```

Replace `your_table_name` with the actual name of your table.

Codeigniter

Ques:- How we can connect multiple databases in codeigniter?

Asked In :- Aptroid,

Right Answer:
In CodeIgniter, you can connect to multiple databases by configuring them in the `database.php` file located in the `application/config` directory. You can define multiple database connections as follows:

```php
$db['default'] = array(
'dsn' => '',
'hostname' => 'localhost',
'username' => 'user1',
'password' => 'pass1',
'database' => 'database1',
'dbdriver' => 'mysqli',
// other settings...
);

$db['second_db'] = array(
'dsn' => '',
'hostname' => 'localhost',
'username' => 'user2',
'password' => 'pass2',
'database' => 'database2',
'dbdriver' => 'mysqli',
// other settings...
);
```

To use the second database in your model or controller, load it like this:

```php
$this->load->database('second_db

Codeigniter

Ques:- How to extend the class in codeigniter?

Asked In :-

Right Answer:
To extend a class in CodeIgniter, create a new file in the `application/core` directory and define your class with the same name as the class you want to extend, followed by the suffix `_MY_` (or `_MY_` if you have set a custom prefix). For example, to extend the `CI_Controller` class, create a file named `MY_Controller.php` and define your class like this:

```php
class MY_Controller extends CI_Controller {
// Your custom code here
}
```

Make sure to load your extended class in your controllers by extending `MY_Controller` instead of `CI_Controller`.

Codeigniter

Ques:- How to link images/css/javascript from a view in codelgniter?

Asked In :-

Right Answer:
To link images, CSS, and JavaScript from a view in CodeIgniter, use the base URL helper function. Here’s how you can do it:

1. Load the URL helper in your controller:
```php
$this->load->helper('url');
```

2. In your view file, link to your assets like this:
```html
<link rel="stylesheet" type="text/css" href="<?php echo base_url('assets/css/style.css'); ?>">
<script src="<?php echo base_url('assets/js/script.js'); ?>"></script>
<img src="<?php echo base_url('assets/images/image.png'); ?>" alt="Image">
```

Make sure to adjust the paths according to your directory structure.

Codeigniter

Ques:- What do you mean by inhibitor in codeigniter?

Asked In :- tact.ai,

Right Answer:
In CodeIgniter, an inhibitor is a feature that allows you to prevent certain actions or processes from occurring, such as stopping a controller from executing or blocking access to specific routes based on conditions.

Codeigniter

Ques:- How to enable error log in codeigniter?

Asked In :-

Right Answer:
To enable error logging in CodeIgniter, open the `application/config/config.php` file and set the following configuration:

```php
$config['log_threshold'] = 1; // Change the number according to the level of logging you want
```

You can set it to:
- 0 = Disables logging
- 1 = Error Messages (including PHP errors)
- 2 = Debug Messages
- 3 = Informational Messages
- 4 = All Messages

Make sure the `application/logs` directory is writable by the web server.

Codeigniter

Ques:- Explain how to create custom 404 page in codeigniter?

Asked In :-

Right Answer:
To create a custom 404 page in CodeIgniter, follow these steps:

1. Create a new view file for your custom 404 page, e.g., `error_404.php`, in the `application/views/errors/html/` directory.

2. In the `error_404.php` file, design your custom error message.

3. Open the `application/config/routes.php` file and set the 404 override by adding the following line:
```php
$route['404_override'] = 'your_controller/your_method';
```
Replace `your_controller/your_method` with the controller and method that will handle the 404 error.

4. In the specified controller method, load the custom 404 view:
```php
public function your_method() {
$this->load->view('errors/html/error_404');
}
```

Now, when a 404 error occurs, your custom page will be displayed.

Codeigniter

Ques:- How to create custom 404 page in codeigniter?

Asked In :-

Right Answer:
To create a custom 404 page in CodeIgniter, follow these steps:

1. Create a new view file for your custom 404 page, e.g., `error_404.php`, in the `application/views/errors/html/` directory.

2. In the `application/config/routes.php` file, set the custom 404 page by adding the following line:
```php
$route['404_override'] = 'your_controller/your_method';
```

3. In the specified controller and method, load the custom 404 view:
```php
public function your_method() {
$this->load->view('errors/html/error_404');
}
```

Now, when a 404 error occurs, your custom page will be displayed.

Codeigniter

Ques:- What is hooks and how we can configure hooks in codeigniter?

Asked In :- Spiro System, briskminds software solutions pvt. ltd.,

Right Answer:
Hooks in CodeIgniter are a way to extend the framework's functionality without modifying the core files. They allow you to execute custom code at specific points during the execution of the application.

To configure hooks in CodeIgniter:

1. Enable hooks by setting `$config['enable_hooks'] = TRUE;` in the `application/config/config.php` file.
2. Define your hooks in the `application/config/hooks.php` file. For example:

```php
$hook['post_controller_constructor'][] = array(
'class' => 'MyHookClass',
'function' => 'my_hook_function',
'filename' => 'MyHookClass.php',
'filepath' => 'hooks',
'params' => array()
);
```

3. Create the hook class and function in the specified file path.

Codeigniter

Ques:- How we can get ip address in codeigniter?

Asked In :-

Right Answer:
You can get the IP address in CodeIgniter using the following code:

```php
$ip_address = $this->input->ip_address();
```

Codeigniter

Ques:- How to install codeigniter? Explain step by step.

Asked In :-

Right Answer:
1. **Download CodeIgniter**: Go to the official CodeIgniter website and download the latest version of CodeIgniter.

2. **Extract Files**: Unzip the downloaded file to your desired location on your server or local development environment.

3. **Set Up Configuration**:
- Rename the `env` file to `.env` if it exists, or create a new file for environment settings.
- Configure the `baseURL` in the `app/Config/App.php` file to match your application URL.

4. **Set Permissions**: Ensure that the `writable` directory has the correct permissions (usually 755 or 775) to allow the application to write logs and cache files.

5. **Database Configuration**: Open `app/Config/Database.php` and set your database connection settings (hostname, username, password, database name).

6. **Access the Application**: Open your web browser and navigate to the URL where you installed CodeIgn

Codeigniter

Ques:- What is the latest version of codelgniter? Lists its new features.

Asked In :-

Right Answer:
The latest version of CodeIgniter is 4.4.0. New features include:

1. Improved performance and speed.
2. Support for PHP 8.1 and 8.2.
3. Enhanced routing capabilities.
4. New built-in validation rules.
5. Improved error handling and logging.
6. Support for environment variables.
7. Updated database features and query builder enhancements.

Codeigniter

Ques:- What do you mean by drivers?

Asked In :- Algorithmic Trading Strategies Pty,

Right Answer:
In CodeIgniter, drivers are classes that provide a way to extend the functionality of the framework by encapsulating specific features or services, allowing for better organization and reuse of code.

Codeigniter

Ques:- What is the default controller used in codeigniter? How we can change it?

Asked In :-

Right Answer:
The default controller in CodeIgniter is `Welcome`. You can change it by modifying the `config/routes.php` file and setting a new default controller using the `$route['default_controller']` variable.

Codeigniter

Ques:- How we can load multiple helper files in codelgniter?

Asked In :-

Right Answer:
You can load multiple helper files in CodeIgniter by using the `load->helper()` method with an array of helper names. For example:

```php
$this->load->helper(array('url', 'form', 'file'));
```

Codeigniter

Ques:- What do you mean by get_instance in codeigniter?

Asked In :-

Right Answer:
`get_instance()` is a function in CodeIgniter that returns the reference of the CodeIgniter super object, allowing access to the framework's core components, libraries, and helpers from within your custom classes or functions.

Codeigniter

Ques:- How to add / link an images/css/javascript from a view in ci?

Asked In :-

Right Answer:
To add or link images, CSS, or JavaScript in a CodeIgniter view, use the base URL helper function. First, ensure the URL helper is loaded in your controller or autoloaded. Then, use the following syntax in your view:

```php
<link rel="stylesheet" type="text/css" href="<?php echo base_url('assets/css/style.css'); ?>">
<script src="<?php echo base_url('assets/js/script.js'); ?>"></script>
<img src="<?php echo base_url('assets/images/image.png'); ?>" alt="Image">
```

Replace `'assets/css/style.css'`, `'assets/js/script.js'`, and `'assets/images/image.png'` with the correct paths to your files.

Codeigniter

Ques:- What is the cli?

Asked In :-

Right Answer:
CLI stands for Command Line Interface. In CodeIgniter, it allows developers to interact with the framework using command line commands for tasks like running migrations, generating controllers, and other administrative functions.

Codeigniter

Ques:- How to read, write or remove session in codeigniter?

Asked In :-

Right Answer:
To read, write, or remove sessions in CodeIgniter, you can use the following methods:

1. **Write a session:**
```php
$this->session->set_userdata('key', 'value');
```

2. **Read a session:**
```php
$value = $this->session->userdata('key');
```

3. **Remove a session:**
```php
$this->session->unset_userdata('key');
```

4. **Destroy all sessions:**
```php
$this->session->sess_destroy();
```

The CodeIgniter category on takluu.com is tailored for web developers preparing for interviews and jobs requiring knowledge of the CodeIgniter PHP framework. Known for its lightweight and fast performance, CodeIgniter is widely used to build dynamic web applications with the Model-View-Controller (MVC) architecture.

This section covers important topics such as CodeIgniter installation, MVC framework basics, routing, controllers, models, views, database interaction, form validation, and session management. You’ll also find questions related to security features, error handling, libraries, and helpers that are critical in real-world applications.

Interviewers often test candidates on practical scenarios such as:

“How do you create and manage routes in CodeIgniter?”
“Explain the role of controllers and models.”
“How does CodeIgniter handle security and data validation?”

Our content simplifies complex framework concepts through clear explanations, code snippets, and example projects. Whether you are a fresher or an experienced developer, this category will help you strengthen your foundation and prepare effectively for technical rounds.

At Takluu, we keep the CodeIgniter content updated with the latest version features and best practices to ensure you stay ahead in your career and interview preparation.

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