Username and password authentication script

[eluser]bhakti.thakkar[/eluser]
Dear all,
I am a new bie to CI. can some one help me with complete code of validating a username script. if username present in the DB then make entry in the LoginHistory_T table and redirect him to the main.php and if not give him a error message.

My three files (MVC) are:
mlogin.php
login_view.php
login.php

mlogin.php code:

Code:

<?php

    class Mlogin extends Model
    {

        function __Construct()
        {
            parent::Model();
        }
        
        function get_users($username)
        {
            $this->load->database();
            $this->db->select('Username_VC');
            $this->db->from('Users_T');
            $query = $this->db->get();
            return $query->row();
        }
    
        function get_last_ten_entries()
        {
            $this->load->database();
            $query = $this->db->get('Users_T');
            return $query->result();
//            print $query->num_rows();
        }
        
        function check_login_data($username, $password)
        {    

            $query = $this->db->select('Username_VC, Password_VC');
            $query = $this->db->from('Users_T');
            $query = $this->db->where('Username_VC', $username);
//            $query = $this->db->where('Password_VC', $password);
            $query = $this->db->get();
            
            if($query->num_rows() > 0)
            { return $query->result(); }
            else
            { return false;}
        }
    }


    

    function addUsersHistory(){
      $now = date("Y-m-d H:i:s");
      $data = array(
        'Username' => $this->input->xss_clean($this->input->post('username')),
        'RemoteAddr_VC' => $this->input->ip_address(),
        'LoginDate_DT' => $now
      );

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


?>

code in login.php

Code:

<?php

class Login extends Controller {

    function Login()
    {
        parent::Controller();    
        $this->load->helper('url');

    }
    
    function index()
    {
        $data['base']       = $this->config->item('base_url');
        $data['css']        = $this->config->item('css');        
        
        $this->load->helper(array('form', 'url'));        // load form
        $this->load->library('validation'); // load validations
              $rules['username'] = 'trim|required|max_length[12]|xss_clean|callback__check_logindata';
              $rules['password'] = 'trim|required|md5';

            // set values for repopulating fields

            $fields['username']='Username';
            $fields['password']= 'Password ';


            $this->validation->set_fields($fields);
              $this->validation->set_rules($rules);
            
    
        if ($this->validation->run() == TRUE)
        {            
            //$this->load->view('checkuser' , $data);
            $this->load->model('Mlogin','',TRUE);
            $password = $this->validation->password;
            $username = $this->validation->username;
            if ($this->Mlogin->check_login_data($username, $password) == FALSE)
            {
                $this->validation->set_message('_check_logindata', 'Username and Password might be incorrect!');
                return FALSE;
            }


//            $this->Mlogin->addHistory();
           // redirect('welcome/thankyou','refresh');



        }
        else
        {
            $this->load->view('login_view' , $data);
        }
    }


     function _check_logindata($username)
        {
          
        $username = $this->input->post('username');
        $password = $this->input->post('password');
            
            $this->load->model('Mlogin');
            if ($this->Mlogin->check_login_data($username, $password) == FALSE)
            {
                $this->validation->set_message('_check_logindata', 'Username and Password might be incorrect!');
                return FALSE;
            }
            else
            {
                return TRUE;
            }
        }

}
?>

there is some mistake somewhere. i get the error message:
Severity: Notice

Message: Undefined property: Mlogin::$db

Filename: models/mlogin.php

Line Number: 31


my DB connection is fine. i printed the number of records in a table and it did print

can some one help me to rectify my code or help me with some sample script link

Million Thanks in advance