Question

If I need to keep member purchase history but also wanna keep my database as efficient as possible (3rd Normal Form) how would I do that keeping out repeating data? This is what I came up with:

Bold = Primary Key

Member(memberID, firstName, lastName, address, city, state, zip)

History(historyID, purchase, date, amount)

MemberHistory(memberID, historyID)

The thing with this is my history table will mean nothing on it’s own and the joined table seems like it would have a bunch of repetition. Anybody 1) see problems with this design and 2) can inform me on a better way to keep a members history?

Answer 1

Get rid of MemberHistory, like so.

Member(memberID(PK), firstName, lastName, address, city, state, zip)

History(historyID(PK), memberID(PK/FK), purchase, date, amount)

there is no many-to-many relationship, so you won’t need MemberHistory