- Consider a relation schema R(A,B,C,D) and a set F of functional dependencies
- Aim to find all keys (minimal superkeys),
- by determining closures of all possible X subsets of R’s attributes, e.g.
- A+, B+, C+, D+,
- AB+, AC+, AD+, BC+, BD+, CD+
- ABC+, ABD+, BCD+
- ABCD+
In Focus
3.1.12. Function dependency