43. Table Q{A , B , C , D} and a set of functional dependencies A → B, C D → C The closure of {A D } is: a) A D b) A D B C c) B C d) None of the above 44. Consider the relation student(sno, sname, cname, cno) where (sno, cno) or (sname, cname) are candidate keys. There are functional dependencies within the keys. Giáo Trình Cơ Sở Dữ Liệu Trang 105 Biên soạn : Phan Tấn Quốc- Trường Cao Đẳng Kỹ Thuật Cao Thắng The highest normal form whose requirements this relation satisfies is: (a) 1NF (b) 2NF (c) 3NF (d) BCNF 45. Let R be a relation with attributes (B,I,N,R,U,L) and let the following functional dependencies hold. B → I B → N N R → U N R → L I → U Given the above functional dependencies, which of the following functional dependencies does not hold: a) N R → U L b) B R → L c) B → U d) I→ N R 46. Suppose relation R(S,G,F,Y,N) has the following functional dependencies: S → G G → F G F → S S → Y N → S Y → N Which of the following is not a key? a) N b) G,F c) S d) Y 47. Table TT {A , N , H , K , J , O , X } and a set of functional dependencies A, N → O, X Giáo Trình Cơ Sở Dữ Liệu Trang 106 Biên soạn : Phan Tấn Quốc- Trường Cao Đẳng Kỹ Thuật Cao Thắng J → A , N, H H, O → K, X H, K, X → O A, N, X → J The closure of {A N } is: e) A H K X J O f) A N H K X J g) A N H X J O h) A N H K X J O 48. Consider the follow attributes and functional dependencies: A B C D E F H A→ D AE → H DF → BC E → C H → E List all keys (not superkeys): 49. (Đề 48) Consider the decomposition into 3 relations: (AD) (EC) (ABEFH). Is this decomposition in (a) BCNF (b) 3NF (c) 1NF (d) None of the above . dependencies within the keys. Giáo Trình Cơ Sở Dữ Liệu Trang 105 Biên soạn : Phan Tấn Quốc- Trường Cao Đẳng Kỹ Thuật Cao Thắng The highest normal form whose requirements this relation satisfies. Y 47. Table TT {A , N , H , K , J , O , X } and a set of functional dependencies A, N → O, X Giáo Trình Cơ Sở Dữ Liệu Trang 106 Biên soạn : Phan Tấn Quốc- Trường Cao Đẳng Kỹ Thuật Cao Thắng. DF → BC E → C H → E List all keys (not superkeys): 49. (Đề 48) Consider the decomposition into 3 relations: (AD) (EC) (ABEFH). Is this decomposition in (a) BCNF (b) 3NF (c) 1NF (d) None