[SOLVED] $this->db->insert() adds all global fields from controller

[eluser]yarinb[/eluser]
I assumed that stripping down $_POST object into $user object which holds only the fields that I need for the insert will work as expected, but it doesn't.

since I must have base_url and base_uri in my controllers, how can I insert only the fields I choose from $_POST and not any other arbitrary fields from my controllers?

what's the best practice anyway to insert data with active record class? All tutorials and examples do the same as I do, but they don't have additional variables in the controller...