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 insert() method accepts the associative array of data and is passed into this method as the only parameter to create a new row of data in the database.

The array’s keys must match the name of the columns in a $table, while the array’s values are the values to save for that key:




$data = [
    'username' => 'darth',
    'email'    => '',

Create a new row of data in the database

1. Create a user_info table in the MySQL database.

CREATE TABLE `user_info` ( 
`first_name` VARCHAR(255) NOT NULL , 
`last_name` VARCHAR(255) NOT NULL , 
`email` VARCHAR(255) NOT NULL , 
) ENGINE = InnoDB;

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

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

3. Create an add.php file in app/Views/ directory

<!DOCTYPE html>

    <title>Add user</title>

    <form method="post" action="<?php echo base_url('user/save'); ?>">
        <table width="600" border="1" cellspacing="5" cellpadding="5">
                <td width="230">First Name</td>
                <td width="329">
                    <input type="text" name="txtFirstName" />
                <td>Last Name</td>
                    <input type="text" name="txtLastName" />
                <td>Email ID</td>
                    <input type="email" name="txtEmail" />
                <td colspan="2" align="center">
                    <input type="submit" name="btnAddUser" value="Add user" />


4. 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;

    function add($data) {
        return $this->db

5. 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() {
        echo view('add');

    public function save() {
        $first_name = $this->request->getPost('txtLastName');
        $last_name  = $this->request->getPost('txtLastName');
        $email      = $this->request->getPost('txtEmail');
        $data = [
            'first_name'        => $first_name,
            'last_name'     => $last_name,
            'email'         => $email,

        $result = $this->userModel->add($data);
        if($result) {
            echo "New user is registered successfully.";
        } else {
            echo "Something went wrong";