Incrementing db value

[eluser]unknownserv[/eluser]
Is it possible to update a table and increment a value by 1 with active record?
As the update data i'm using

Code:

<?php
$data = array('field' => 'field + 1');
?>

The problem with this is that when CI does the query it does it as SET 'field' = 'field + 1', when it should be SET 'field' = field + 1 for it to work.

Any ideas?
Cheers.