GATE CSE 2020: Revision Quiz 3 for GATE & PSU CS Exams

Question 1

Consider the following FD set on R(A,B,C)

The canonical cover of this set is

Question 2

The switching expression corresponding to

f(A, B, C, D) = Σ (1, 4, 5, 9, 11, 12) is

Question 3

The output F of the 4-to-1 MUX shown in figure is

Question 4

An index file consists of :

Question 5

Identify the minimal product-of-sums function described by the K-map given in the figure. Where ϕ is don’t care

Question 6

Consider the following relational database: employee(e-name, street, city)
works(e-name, c-name, salary)
company(c-name, city)
manages(e-name, m-name)
Query: Find the name of all the employees who works in First Corporation bank.
Which of the following is true wrt to tuple relational calculus.

Question 7

Consider the following Statements:
1) An Entity Integrity constraint states that primary key value cannot be null.
2) A referential integrity constraint is specified between two relations.
3) A foreign key cannot be used to refer its own relation.
Which of the above statement are correct?

Question 8

How many 3-to-8 line decoders with an enable input are needed to construct a 6-to-64 line decoder without using any other logic gates?

Question 9

The literal count of a boolean expression is the sum of the number of times each literal appears in the expression. For example, the literal count of (xy + xz’) is 4. What are the minimum possible literal counts of the product-of-sum and sum-of-product representations respectively of the function given by the following Karnaugh map ? Here, X denotes “don’t care”

Question 10

Suppose you are given an empty B+-tree where each node (leaf and internal) can store up to 5 key values. Suppose values 1,2,….. 10 are inserted, in order, into the tree, Show the tree pictorially
(i) After 6 insertions, and
(ii) After all 10 insertions
Do NOT show intermediate stages.