php - Update query not working in codeigniter -

i trying update record id using clause no success. echo last query , try in phpmyadmin run sql query not success. have check table name column names, fine.

    $updatedata = array(      'task_forward_to'=> 9,     'task_forward_by'=>8     );             $this->db->where('id', 32);     $this->db->update('tasks', $updatedata);      echo $this->db->last_query();      "update tasks set task_forward_to = 9, task_forward_by = 8 id = 32 

data types of both columns int(11)