[eluser]Michael Wales[/eluser]
This isn't a complete example, just the parts that matter
Code:
$rules['email'] = 'required|valid_email|callback__check_email';
$this->validation->set_rules($rules);
function _check_email($email) {
$query = $this->db->get_where('users', array('email'=>$email), 1, 0);
if ($query->num_rows() != 0) {
$this->validation->set_message('_check_email', 'That email address has already been registered.');
return FALSE;
}
return TRUE;
}
Should be enough to get you on your way.