更新查询无法在codeigniter中工作

Question

I am trying to update record with id using where clause but no success. I echo the last query and try that in phpmyadmin run sql query but not success. I have check the table name column names, all are 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 where id = 32

data types of both columns are int(11)