I wonder about the extra table myself. I've not made many posts here, but I felt I should put in my two cents (not that that is worth much these days). If you can be certain that there will be a fairly high percentage of students living together, then perhaps it has merit. However, if the probability is rather on the low side, the extra table would use a lot more storage space...duplicating every single person_id, plus every single address_id. Sometimes we tend to normalize a database to death. Some do it just for the sake of normalizing. I'm not accusing you of such a thing, just suggesting that it happens, probably more than some would like to admit.

Just a thought. 🙂

Dana