Monday, 24 March 2014

Functional Dependency - Quiz 2

RegNo
SName
Gen
PR
Phone
PManager
R1
Sundar
M
BTech
9898786756
Kumar
R2
Ram
M
MS
9897786776
Kumar
R3
Karthik
M
MCA
8798987867
Steve
R4
John
M
BSc
7898886756
Badrinath
R5
Priya
F
MS
9809780967
Kumar
R6
Ram
M
MTech
9876887909
Jagdeesh

Relational Database Design - Functional Dependency Quiz 2


1. Which of the following functional dependencies are held in the given table?
    RegNo --> SName Gen PR
    RegNo --> Phone
    PManager SName --> RegNo
    All of the above

2. {(RegNo --> SName Gen PR Phone PManager), (Phone --> RegNo SName Gen PR PManager), (PR --> PManager)}. If these are the functional dependencies of the given relation, which of the following is the Primary key?
    RegNo
    Phone
    (RegNo Phone)
    (RegNo PR)

3. Assume that (RegNo, SName), (PR, Gen), (Phone, RegNo), and (RegNo) are the super keys for a relation. Which of the following is the candidate key for this relation?
    SName
    RegNo
    PR
    Phone

4. For a table r(A, B, C, D, E), if (A, B), (A, B, E), and (C, D, E) are the candidate keys, which of the following would be the Primary key?
    ABE
    CDE
    AB
    None of the above

5. For a table ST(B, O, I, S, Q, D), if S --> D, I --> B, IS --> Q, and B --> O, then what are the keys for ST?
    IS
    IB
    BO
    SD

6. In a functional dependency with multiple attributes, which of the following is true?
    More than one attribute on LHS may be essential
    More than one attribute on RHS may be essential
    Both are essential
    None of the above

7. If A --> B, B --> C, and C --> D, then which of the following is true?
    A --> C
    B --> D
    A --> D
    All of the above

8. If A --> BC, then A --> B and _________ is Decomposition rule.
    B --> C
    B --> A
    A --> C
    All of the above

9. Union rule, Decomposition rule, and Pseudotransitivity rule can be proved using Armstrong's axioms.
    TRUE
    FALSE
    TRUE
    FALSE

10. In a relational schema R(A, B, C, D, E) with functional dependencies AC --> E, C --> D, and D --> A, which of the functional dependencies has an extraneous attribute?
    AC --> E
    C --> D
    D --> A
    None of the above

Score =

Correct answers:

1 comment:

  1. Sir, can you clarify the answer for 2nd question? With the given data, even Phone yields all other attributes. So why is it Reg No? It can be either of them right?

    ReplyDelete

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