Loading model in CodeIgniter is not automatically executing the index() method in that class

I am trying to insert data into a table named class_record in a MySQL database. My controller class aadd_record is written in my add_record.php file.

class Add_record extends CI_Controller
{
    function __construct()
    {
        parent::__construct();
    }
        
    function index()
    {
        $this->load->model('add_record_model');
    }
}

My model add_record_model is as below:

class add_record_model extends CI_Model
{
    function __construct()
    {
        parent::__construct();
    }

    function index()
    {
        $data = array(
            'roll_number' => 15,
            'student_name' => 'Dhrubajyoti Baishya',
            'branch_code' => 'CS'
        );
        
        $this->db->insert('class_record', $data);
    }
}

But when I type http://localhost/codeigniter/index.php/add_record in the url, data is not inserted into the database. What is the problem?

You're not actually doing anything in the controller and models don't have index functions the way you're thinking.

You want something like this:

class Add_record extends CI_Controller
{
    function __construct()
    {
        parent::__construct();
    }

    function index()
    {
        $this->load->model('add_record_model');
        $this->add_record_model->insertRecords();
    }
}



class add_record_model extends CI_Model{

function __construct(){
    parent::__construct();
}
function insertRecords(){
    $data = array(

        'roll_number' => 15,
        'student_name' => 'Dhrubajyoti Baishya',
        'branch_code' => 'CS'
    );

    $this->db->insert('class_record',$data);
}
}

The controller does what it says it controls things. By loading the model all you are doing is exposing the models functions to the controller to use directly. Honestly you would pass the data to the model from the controller as well, the function you have is a good little test function but does nada really. How you really want to be doing it is something along these lines.

class Add_record extends CI_Controller
{
    function __construct()
    {
        parent::__construct();
    }

    function index()
    {
        $data = array(

        'roll_number' => 15,
        'student_name' => 'Dhrubajyoti Baishya',
        'branch_code' => 'CS'
    );
        $this->load->model('add_record_model');     
        $this->add_record_model->insertRecords($data);
    }
}



class add_record_model extends CI_Model{

function __construct(){
    parent::__construct();
}
function insertRecords($data){       

    $this->db->insert('class_record',$data);
}
}