How to perform inline editing in Codeigniter PHP using AJAX?

I saw an example in native PHP which allows inline editing or records and also updates them. PHP Inline Editing Now as per this code i have a ajax function which calls the update file whenever the content is updated below is the script :

    <script src="http://code.jquery.com/jquery-1.10.2.js"></script>
    <script>
    function showEdit(editableObj) {
        $(editableObj).css("background","#FFF");
    } 

    function saveToDatabase(editableObj,column,id) {
        $(editableObj).css("background","#FFF url(<?php echo site_url('img/loaderIcon.gif');?>loaderIcon.gif) no-repeat right");
        $.ajax({
            url: "<?php echo(site_url('Inlinedit/updateDb'));?>",
            type: "POST",
            data:'column='+column+'&editval='+editableObj.innerHTML+'&id='+id,
            success: function(data){
                $(editableObj).css("background","#FDFDFD");
            }        
       });
    }
    </script>

THe Model :

public function inline( $column, $editval, $id )
        {
            $result = mysql_query("UPDATE users set $column = $editval WHERE  id=$id");
        }

the Controller:

<?php

class Inlinedit extends Admin_Controller {

 public function __construct()
 {
    parent::__construct(); 
 }


      public function updateDb()
      {
             $column = $this->input->post('column');
             $editval = $this->input->post('editval');
             $id = $this->input->post('id');

             $this->load->model('user_m');                     
             $this->user_m->inline( $column, $editval, $id );

             return;
      }

}

Answer:

First of all you should understand you cant call model function bypassing controller. for that what you have to do is

1. Create a new method in controller.(One time use)
2. Inside that method just use method calling your model.

ex
In controller

public function just_a_method()
{
    $this->Model_name->inline();/just call method
}

and in view

$.ajax({
    url: "<?php echo base_url()?>controller/just_a_method",