> Data should be stored as normalized as possible, but queries are supposed to denormalize to present information in the desired format. The desired format dep

> Data should be stored as normalized as possible, but queries are supposed to denormalize to present information in the desired format. The desired format depends on the application. At this point a substantial portion of all SQL queries are generated by (and the results consumed by) ORMs. For that use case having results that include Products and Categories separately (so you can instantiate Product and Category objects) is more useful than a single table.