Message: Undefined property: Blog::$db

[eluser]parifuture[/eluser]
can some1 post the answer 4r the same que?

I am getting this error in the apache error log
[Mon Jun 13 09:55:03 2011] [error] [client 127.0.0.1] PHP Fatal error: Call to a member function query() on a non-object in /home/parikshit/workspace/Webpurify/application/models/profane_model.php on line 17

this is my code

Code:

<?php

class Profane_model extends CI_Model {
    
    function getdata() {
        $q = $this->db->get('tags');
        
        if($q->num_rows() > 0) {
            foreach($q->result() as $row) {
                $data[] = $row;
            }
            return $data;
        }
    }
    
    function putdata($var) {
        $q = $this->db->query("INSERT INTO `sys_tag`.`tags`(`id` ,`s_tag`, `profane`)VALUES (NULL , '$var', 'F')");
        return 1;
    }
}