PHP Message: Undefined property: Update_form::$update_model - codeigniter

Question

Please help me on this error:
A PHP Error was encountered
Severity: Notice
Message: Undefined property: Update_form::$update_model
Filename: controllers/update_form.php
Line Number: 15
Backtrace:
File: C:\xampp\htdocs\306\application\controllers\update_form.php
Line: 15
Function: _error_handler
File: C:\xampp\htdocs\306\index.php
Line: 315
Function: require_once
An uncaught Exception was encountered
Type: Error
Message: Call to a member function rest() on null
Filename: C:\xampp\htdocs\306\application\controllers\update_form.php
Line Number: 15
Backtrace:
File: C:\xampp\htdocs\306\index.php
Line: 315
Function: require_once
here is the code:
update.php
<?php
class Update extends CI_Controller
{
function __construct()
{
parent::__construct();
$this->load->helper(array('html','form','url'));
$this->load->library('table');
$this->load->model('update_model');
}
function index()
{
$this->table->set_heading('Books Name','Author','Edit Records');
$tstyle= array(
'table_open' => '<table border="1" align="center" cellpadding="4" cellspacing ="0">'
);
$this->table->set_template($tstyle);
$answer = $this->update_model->select();
foreach ($answer as $row)
{
$link = anchor(base_url().'update_form/update_function/'.$row->id,'Edit');
$this->table->add_row($row->name,$row->author,$link);
}
echo $this->table->generate();
}
}?>
update_model.php
<?php
/**
*
*/
class Update_model extends CI_Model
{
function __construct()
{
parent::__construct();
}
function select()
{
$this->db->select();
$this->db->from('books');
$query = $this->db->get();
return $query->result();
}
function rest($id)
{
$this->db->select();
$this->db->from('books');
$this->db->where('id',$id);
$query1= $this->db->get();
if($query1->num_rows() ==1)
{
return $query1->result();
}
}
}?>
update_form.php
<?php
class Update_form extends CI_Controller
{
function ___construct()
{
parent::__construct();
$this->load->helper('form');
$this->load->model('update_model');
}
function update_function($id)
{
$answer = $this->update_model->rest($id);
foreach ($answer as $row)
{
echo form_open();
echo form_label('Book','book');
echo form_input('book', $row->name);
echo form_label('Author','author');
echo form_input('author', $row->author);
echo form_submit('submit','Update');
echo form_close();
}
}
}?>

Answer 1

You need to check line by line code which i am to add below
Controller :
Add below line on the top of the page of controller
if ( ! defined('BASEPATH')) exit('No direct script access allowed');
**check you controller class name uppercase first letter.
**
$this->load->model('update_model');
Now update_model.php
Add : $this->db->select('*')
Try to load the model on the method or you can try to check autoload.php files..
It is showing line no 15 on update_form.php :
Create your function public in the controller.
Check or mark accepted if it works