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## Monday, March 24, 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?

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