Most easier to show idea on an example.
Model data:
id|articul|title
1|gx10fz6|some1
2|xc65fd3|some2
3|tr44ty6|some3
Controller code:
$products=Product::model()->findAll(array(
'condition'=>'isPublished',
'index'=>'articul',
));
CVarDumper::dump($products);
Result:
Array
(
['gx10fz6'] => ...
['xc65fd3'] => ...
['tr44ty6'] => ...
)