You might be confusing CASC with the MySQL database(s) that are wrapped in the re-pack. These are very different things, and I'm sorry if I caused some confusion about it calling CASC 'a database'. CASC is most assuredly the system that blizzard created to store the assets (sounds, textures, meshes, etc.) starting in Warlords of Draenor and continuing for every client version there after. The CASC system doesn't actually have anything to do with the server side of things at all, it is entirely within the game client.
Here's a bit more concise link to the CASC viewer then the previous page I suggested (that may have been a bit over-informational):
This tool originates from here A tool for browsing files and extracting data, called CascView is available, supporting all Blizzard games. CascView features browsing of local and online storages, searching files, extracting files, viewing BLP images and more. Note that CascView is...
www.hiveworkshop.com
Using this program should operate pretty similarly to how you would go about looking at the data inside an .MPQ file. Beyond that, it's just a matter of finding the .blp files you are searching for.
Hopefully this might be a bit more comprehensible then my previous reply. I really am sorry that my information is a bit vague and not really instructive, I'm still not very well versed with CASC as I have to feel my way around to make sure I actually give you accurate information.