Question

Note that we follow the convention of denoting the set of attributes {A, B, C} by ABC when we write FDs but not when we write schemas. Given the following set set F of FDs on schema R= (A, B, C, D, E,G): A + BC AB + CD B +C E →D G +C EG → AD Answer the following questions. Questions 1-4 require a formal proof or disproof. A proof may be given either via Armstrong's Axioms or from the formal definition of a functional dependency. A disproof is given by providing a specific example instance of a relation r(R) that satisfies F but does not satisfy the FD that you are attempting to disprove. 1. Prove or disprove: F= A +D 2. Prove or disprove: F GD + C 3. Prove or disprove: F + C + A 4. Prove or disprove: F=G + BC 5. List all candidate keys for R given F. 6. Decompose R into a BCNF design. 7. Is your BCNF design dependency preserving? Why or why not? 8. Give a canonical cover for F. Justify each claim of an extraneous attribute. 9. Give a 3NF design for R.

please do question 4.

Answer 1

Answering Question 4.
solution is here Here - F.D. Set R = = (A, B, C, D, E,G) A » Bc A B CD Btc ED G-C EGT AD Question иң ч. 4. Proue roue or on dis proue distreue I F G G BC BC - To proue or dis proue , take closure of G if it will give BC, then f is valid other wise invalid. Now Gt → BC » (i) (i) = GBC is a valid FD Therefore F G7BC is true.