Health Data Clinic - Book 8: Advanced Normalization

Third Normal Form is not the finish line. A few problems slip past it, and this book closes them. You begin with the gap: tables with overlapping candidate keys, where a determinant is not a candidate key at all. Candidate keys and determinants are defined precisely, the Boyce-Codd rule is stated, a real violation is shown, and the fix is carried out and then tested with a lossless join so you can prove the original data comes back. Next comes the multi-valued dependency, where one table quietly holds two independent lists, the trouble that causes, and Fourth Normal Form as the answer. Fifth Normal Form follows, with join dependency and a three-way relationship that only rebuilds correctly from three separate pieces. The full ladder is drawn in one place, and the last chapter gives an honest answer to how far you should normalize in practice.

Twenty-five A4 pages, in full color. Written in short sentences and plain English, for readers whose first language is not English and clearer for everyone else because of it.

Every query in this book was run against a live database before the page was printed, so the result you read is the result you get. Instant PDF download. By M.R. Sterling.