Change Anomalies
Inconsistencies that result from an operation like update, insertion, or deletion
Example
No clear problem with expressing queries
Problems with data revisions
- Update
- Change name of supplier S1 to ACME
- Need to change all S1
- Insert
- Add item I4 with name Washer
- What about the first 3 columns?
- Delete
- Supplier “Budd” no longer supplies screws
- Do we delete Budd or just the screws?