You can look here, too:
http://www.uesp.net/wiki/Online:Item_Link
It depends on what you want to do. Items like armor and weapons have the same id, but different names (from material) from subtype (includes vet) and level (non-vet).
Potions have the same name, subtype and level but different traits from the potion-effect bitfield.
Trophys items like fishes defining their name and quality by item-id. (There is only one, no variation)
and so on...