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Third Normal Form
Formal Definition
Definition
- A relation schema R is in third normal form (3NF) if
- for all functional dependencies in F+ of the form ,
where R and R, at least one of the following holds:
- is a trivial functional dependency ( )
- contains a key for R
- every B is part of some candidate key of R
BCNF and 3NF
- A BCNF relation is in 3NF
- A 3NF relation is not necessary in BCNF
Notes: