1
GATE CSE 2021 Set 1
MCQ (Single Correct Answer)
+2
-0.67

Consider the relation R(P, Q, S, T, X, Y, Z, W) with the following functional dependencies.

PQ → X; P → YX; Q → Y; Y → ZW

Consider the decomposition of the relation R into the constituent relations according to the following two decomposition schemes.

D1 : R = [(P, Q, S, T); (P, T, X); (Q, Y); (Y, Z, W)]

D2 : R = [(P, Q, S); (T, X); (Q, Y); (Y, Z, W)]

Which one of the following options is correct?

A

D1 is a lossy decomposition, but D2 is a lossless decomposition.

B
Both D1 and D2 are lossless decompositions.
C
Both D1 and D2 are lossy decompositions.
D
D1 is a lossless decomposition, but D2 is a lossy decomposition.
2
GATE CSE 2021 Set 1
MCQ (Single Correct Answer)
+2
-0.67

Let ri(z) and wi(z) denote read and write operations respectively on a data item z by a transaction Ti. Consider the following two schedules.

S1 : r1(x) r1(y) r2(x) r2(y) w2(y) w1(x)

S2 : r1(x) r2(x) r2(y) w2(y) r1(y) w1(x)

Which one of the following options is correct?

A
S1 is conflict serializable, and S2 is not conflict serializable.
B
S1 is not conflict serializable, and S2 is conflict serializable.
C
Both S1 and S2 are conflict serializable.
D
Neither S1 nor S2 is conflict serializable.
3
GATE CSE 2021 Set 1
MCQ (Single Correct Answer)
+2
-0.67

Assume that a 12-bit Hamming codeword consisting of 8-bit data and 4 check bits is d8d7d6d5c8d4d3d2c4d1c2c1, where the data bits and the check bits are given in the following tables:

Data bits

d8

d7

d6

d5

d4

d3

d2

d1

1

1

0

x

0

1

0

1

 

c8

c4

c2

c1

Y

0

1

0


Which one of the following choices gives the correct values of x and y?
A
x is 1 and y is 0.
B
x is 1 and y is 1.
C
x is 0 and y is 1.
D
x is 0 and y is 0.
4
GATE CSE 2021 Set 1
MCQ (Single Correct Answer)
+2
-0.67
Let the representation of a number in base 3 be 210. What is the hexadecimal representation of the number?
A
21
B
528
C
D2
D
15
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