Question

For the following relation schema and dependencies: R(A,B,C,D,E) with MVD’s A→→B and AB→→C and FD’s A→D and AB→E. Do the following:

1. Find all the 4NF violations.
2. Decompose the relations into a collection of relation schemas in 4NF.

Answer 1

To identify the 4NF violations in the given relation schema and dependencies, we need to check if there are any non-prime attributes that are functionally dependent on only a part of a candidate key. To decompose the relations into a collection of relation schemas in 4NF, we can create new relations using the dependencies and their closures.

Step-by-step explanation:

To identify the 4NF violations in the given relation schema and dependencies, we need to check if there are any non-prime attributes that are functionally dependent on only a part of a candidate key. Looking at the given dependencies, we can see that the MVD (Multivalued Dependency) A→→B violates 4NF. To decompose the relations into a collection of relation schemas in 4NF, we can create new relations using the dependencies and their closures.

The new relations can be: R1(A, B) with the MVD A→→B, R2(A, B, C) with the MVD AB→→C, R3(A, D) with the FD A→D, and R4(A, B, E) with the FD AB→E.