is_unique error on update

[venonw]

Hello,

I'm using MY_Model for a script but I have a problem in is_unique validation:
$this->pages_model->from_form(NULL,array('id' => $page_id),array('id' => $page_id))->update();

it seems I can't exclude current DB raw to check for unique validation and it always shows an error. how can I modify it?