Normalization from 1NF to 5NF - Database Cheat Sheet

The full ladder from 1NF to 5NF. A table that passes 3NF but fails BCNF, fixed and guarded by SQLite, a lossless split proven with EXCEPT, a lossy one that invents rows, then 4NF and 5NF, each checked by joining the pieces back.

On the sheet:

- The full ladder: 1NF to 5NF, each form's one-line test

- Candidate keys and determinants: unique, minimal, and alternate keys

- Five dependencies: and the form each one breaks

- The BCNF test: a table that passes 3NF but fails BCNF

- Fix BCNF: the determinant gets its own table

- Lossless join: proven with EXCEPT and a row count

- A lossy split: the spurious rows it invents

- MVD and 4NF: one table per independent list

- Join dependency and 5NF: three pairs rebuild the rows exactly

Two A4 pages, printed front and back, sized to print once and keep beside you while you work. Written in short sentences and plain English, for readers whose first language is not English and clearer for everyone else because of it.

It pairs with the Normalization I: 1NF, 2NF & 3NF and Advanced Normalization books, so you can learn each idea in full and then revise it here in two pages.

Every query on this sheet 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.