MySQL + SQL · Lesson 111
Normal Forms Quick Revision
All Normal Forms at a Glance
A quick revision table of every normal form and the one problem each removes.
Summary Table
| Form | Removes | Rule |
|---|---|---|
| 1NF | repeating groups | atomic values only |
| 2NF | partial dependency | 1NF + full dependency on key |
| 3NF | transitive dependency | 2NF + no non-key → non-key |
| BCNF | overlapping-key anomalies | every determinant is a candidate key |
Summary
- 1NF→atomic, 2NF→no partial, 3NF→no transitive, BCNF→determinant is candidate key.
- Each higher form removes a more subtle anomaly.