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closed set ?

Keyoumu Aisikeer 8 miesięcy temu • zaktualizowano 8 miesięcy temu • 1

We say a set of attributes X is closed ( with respect to a given set of FD’s) If X+= X.

Consider a relation with schema R(A,B,C,D) and unknown set of FD’s. If we are told which set of attributes are closed, we can discover the FD’s. What are the FD’s if

a) All sets of the four attributes are closed

Keyoumu Aisikeer 8 miesięcy temu

To discover the functional dependencies (FDs) based on the given information about closed sets of attributes, we can follow these steps:

(a) All sets of the four attributes are closed:

In this case, if all sets of attributes are closed, it means that no additional FDs can be inferred from the given information. Without any additional information, we cannot determine any specific FDs.

If this answer is correct? why?

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