A schema with problems
Insertion anomaly
How do we represent a label that has not yet signed any artists?
This doesn't work:
| artist |
artist_website |
title |
year |
label |
label_website |
| NULL | NULL | NULL | NULL | Broken Records | broken-records.com |
- The PK is (artist, title).
- PK columns cannot be NULL.
- artist and title are both NULL.
|