How to store facebook user data into database ?

[eluser]Keloo[/eluser]
I've tried something like this:

in the model I'm checking for the id

Code:

public function id_check($id)
{
  $this->db->where('id', $id);
  return $this->db->get('users')->num_rows();
}

and in the controller have something like this:

Code:

function account()
{
  $fb_data = $this->session->userdata('fb_data');

  if((!$fb_data['uid']) or (!$fb_data['me']))
  {

   redirect('home/index');
  }
  else if($this->Facebook_model->id_check($fb_data['me']['id']) < 0 )
  {
   $query = array(
    'id' => $fb_data['me']['id'],
    'fullname' => $fb_data['me']['name'],
    'email' => $fb_data['me']['email']
   );

   $this->db->insert('users',$query);
  
  }
  else
  {
  
   $data = array(
      'fb_data' => $fb_data

    );

   $this->layouts->set_title('My Account');
   $this->layouts->view('account', $data);
  }

}

The problem is, when I'm logging in with another fb account, it doesn't grab the user data and insert it in the DB, because there is data.

I need to check by id. If that ID already exists, don't insert data, but if it doesn't insert it.