Course Content
Introduction to CodeIgniter 4
CodeIgniter is an Application Development Framework. CodeIgniter is a popular and powerful MVC (Model-View-Controller) framework that is used to develop web applications. It is a free and Open-source PHP framework.
MVC (Model-View-Controller)
MVC stands for Model-View-Controller. MVC is an application design model consisting of three interconnected parts. They include the model (data), the view (user interface), and the controller (processes that handle input).
The Session class allows you to maintain a user’s "state" and track their activity while they browse your site.
URI Routing
There is a one-to-one relationship between a URL string and its corresponding controller class/method.
Working with Database
Like any other framework, we need to interact with the database very often and CodeIgniter makes this job easy for us. It provides a rich set of functionalities to interact with the database.
PhpSpreadsheet is a PHP library for reading and writing spreadsheet files. Importing Excel and CSV into MySQL help to save the user time and avoid repetitive work.
CodeIgniter 4
About Lesson

The getResult() and getRow() methods retrieve the data from the database. getResult() method returns the list of data objects and the getRow() method returns the single row.


// Get the list of data
// Get the single data

1. Copy and Paste the following lines in app/Config/Routes.php

$routes->add('user/list', 'User::list');

2. Create a list.php file in app/Views/ directory

<table width="600" border="1" cellspacing="5" cellpadding="5">
    <tr style="background:#CCC">
        <th>Sr No</th>
        <th>Email Id</th>
    <?php $i=1; foreach($result as $row) { 
        echo "<tr>"; 
        echo "<td>".$i. "</td>"; 
        echo "<td>".$row->first_name."</td>";
        echo "<td>".$row->last_name."</td>"; 
        echo "<td>".$row->email."</td>"; 
        echo "<td><a href="<?php echo base_url('user/edit'.$row->id) ?>">Edit</a></td>";
        echo "</tr>"; $i++; } ?>

3. Create a model file UserModel.php in the app/Models/ directory.

namespace AppModels;

use CodeIgniterModel;
use CodeIgniterDatabase\ConnectionInterface;

class UserModel extends Model {
    protected $db;
    public function __construct(ConnectionInterface &$db) {
        $this->db =& $db;

    public function list() {
        return $this->db

4. Create a controller file User.php in the app/Controllers/ directory.

namespace AppControllers;

use AppModelsUserModel;

class User extends BaseController {

    public function __construct() {

        $db = db_connect();
        $this->userModel = new UserModel($db);

    public function add() {

    public function list() {
        $data['result'] = $this->userModel->list();
        echo view('list', $data);