Update two joined tables

[eluser]insub2[/eluser]
I'm having a hard time finding out how to do this.

I can get from the DB with the join and it works as expected.
But I can't update using $this->db->update($table, $insert).

This works for getting:

Code:

function get_profile()
    {

        $this->db->get($this->_prefix.'user');
        $this->db->join($this->_prefix.'user', $this->_prefix.'user.id = '.$this->_prefix.'user_profile.id');
        
        //SELECT name FROM user WHERE id = $id

        $this->db->where('user_name', 'insub2'); //I Know, I just haven't gotten to the point where this is done dynamically

        
        $query = $this->db->get($this->_table);
        
        $row = $query->row();
        
        return $row;
    }

I can't seem to find anyway to update a join or two tables in one query. Is it possible? It seems like it should be.