MAKE SURE THIS ER IS BCNF! IF YOU SEE ANY OBVIOUS FD's WE MISSED NOTE IT AND CHANGE THE DIAGRAM IF NECESSARY (SO IT REMAINS IN BCNF).

eliminate from PurchasedVideo the purchase_date (because we can find it via the trans_id)

_trans_id, _terms_id (add terms_id) -> tkey

_username _video -> (comment, rating)

_terms_id -> video_id, price, duration