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Third Normal Form
Informal Presentation
Motivation
- Decomposition to get to BCNF may not always be desirable
- BCNF decomposition is not dependency preserving, and
- Efficient checking for FD violation on updates is important
- 3NF relaxes BCNF to allow relations that cannot be decomposed
into BCNF relations without losing ability to check each FD
Informal Definition of 3NF
- A relation R is in third normal form if:
Notes: