That pulls the books back in, but doesn't recreate the metadata, which is what I assumed you meant by rebuilding the database. The books are the easy part, it's recreating the metadata that's a hassle.
Week old backups are better than starting from scratch! You can start with the week old data and then just re-add and fix the hundred or so new books you've added since then. It's also a good idea to back up again after any decent size addition so if something like this happens, you don't have to do too much work
As to coming up often, I don't actually see it coming up all that often, but maybe I just haven't been looking hard enough.
I've been using Calibre for over a year and have never had the database get corrupt. If it's happening frequently for you, maybe there's a more fundamental problem with your system?