No limit() method bug in is_unique form validation?

[eluser]RecoilUK[/eluser]
Hi guys

So I am trying to use the is_unique form validation as below ...

Code:

$this->form_validation->set_rules('name', 'Name', 'required|alpha_numeric_relaxed|min_length[3]|max_length[100]|is_unique[businesses.bus_name]');

But I'm getting the following error message in the browser ...

Code:

Fatal error: Call to undefined method CI_DB_mysql_driver::limit() in C:\Users\Steve\http\system\libraries\Form_validation.php on line 954

So it looks like it can't find the limit() method to use it.

Can anybody help?

Thank You