Indian Institute of Technology Madras (IIT-M) 2000 A.M.I.E.T.E Computer Science

(c) 9.999 microseconds
(d) 1.9999 microseconds
2.23. Which of the subsequent is NOT a valid deadlock prevention scheme?
(a) Release all resources before requesting a new resource
(b) Number the resources uniquely and never request a lower numbered resource than the
last 1 requested.
(c) Never request a resource after releasing any resource
(d) Request and all needed resources be allocated before execution.
2.24. provided the subsequent relation instance
xYz
142
153
163
322
Which of the subsequent functional dependencies are satisfied by the instance?
(a) XY-)ZandZ-Y
(b) YZ-XandY-Z
(c) YZ-XandX-)Z
(d) XZ-YandY-X
2.25. provided relations r(w,x) and s(y,z), the outcome of
choose distinct w,x
from r, s
is guaranteed to be identical as r, given
(a) r has no duplicates and s is non-empty
(b) r and s have no duplicates
(c) s has no duplicates and r is non-empty
(d) r and s have the identical number of tuples
2.26 In SQL, relations can contain null values, and comparisons with null values are treated as
unknown. Suppose all comparisons with a null value are treated as false. Which of the
subsequent pairs is not equivalent?
(a) x = five not (not (x = 5)
(b) x = five x > four and x < 6, where x is an integer
(c) x<5 not (x=5)
(d) None of the above
part - B
This part consists of TWENTY ques. of 5 marks every. Attempt ANY FIFTEEN
questions. If more number of ques. are attempted, score off the ans not to be
evaluated, else only the 1st fifteen unscored answers will be considered.
1. A multiset is an unordered collection of elements where elements may repeat any number
of times. The size of a multiset is the number of elements in it counting repetitions.
(a) What is the number of multisets of size four that can be constructed from n distinct elements
so that at lowest 1 element occurs exactly twice?
(b) How many multisets can be consctructed from n distinct elements?
2. Let S be a set of n elements {1, 2, ...., n} and G a graph with two vertices, every vertex
corresponding to a distinct subset of S. 2 vertices are adjacent if the symmetric difference
of the corresponding sets has exactly two elements. Note: The symmetric difference of 2 sets

Earning:   Approval pending.