Health Data Clinic - Book 6: Normalization I: 1NF, 2NF & 3NF

Store a fact twice and one copy will drift. This book makes sure each fact lives in exactly one place. It opens with the three anomalies that redundancy causes on insert, update and delete, then puts an unnormalized clinic table on the page and refuses to leave it alone. You review the keys you need, reach First Normal Form and fix the table to satisfy it, learn what a functional dependency is, and use that idea to find and remove the partial dependency that breaks Second Normal Form. Transitive dependency comes next, and with it Third Normal Form and the fix that clears it. Every step is shown before and after, so you watch the table change rather than take the rule on trust. The pieces are then put back together with a working JOIN, proving nothing was lost along the way. A ladder of the normal forms and a three-step checklist close the book.

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.