Ways to retrieve World of Warcraft Item Information
I was asked question on how to retrieve item information in my World of Warcraft Armory Data Item Update entry and thought I would give a couple of ideas here.
There are a couple of ways that I can see doing this and it really depends on your setup and intent for the data. If you want to mine all the data the item-info.xml takes in one parameter which is i and is an unique integer value for the item. Taking a quick look at my profile the highest value is 33522 and my lowest value is 5976. So you could easily setup a loop to loop from 1 to 40000 and should get the majority of items. The thing to note is this will get you every item including vendor trash.
Another approach would be to only retrieve item data for items that you are using in your dataset. For instance a small guild site where the web host might limit the size of a database. To pull this information, I would use the character profiles of the guild. Items appear in several places on the character-sheet.xml. Specifically they are in the item node under the attributes gem0Id, gem1Id, gem2Id and id. Building off of the character sheet will reduce the total size of the item inventory. This method does require a little more maintenance. For instance patches that change items or when players stop equipping items that have already been recorded. So wiping the dataset periodically would not be a bad idea.

~Saritor
So in short both methods you suggest for building a database of items are feasible for collecting information on ilevel, equip level, the name of the item, and a few other statistics. However, it is not possible to collect the attributes of items from these xml feeds.
http://www.wowarmory.com/item-tooltip.xml?i=32473
Hope this helps