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APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FIRST SEMESTER M.TECH DEGREE EXAMINATION, DECEMBER 2018

Branch: Computer Science & Engineering

Stream(s): Computer Science & Engineering

01CS6103 : Topics in Database
Technology

Answer any twofull questions from each part Limit
answers to the required points.

Max. Marks: 60 Duration: 3 hours

PART A

1. a.Consider the tables R (A, 8, C), SCG, 11) and G, 1) where A, Dand ೮ (7) in ‏تا‎ are
foreign keys referring to the primary keys with the same names.
Show an initial quelY tree for the following query and optimize it using the rules of heuristics:

select 8, E, ©, H, 1 from R, T, S, U where R.A =
U.A

೩೧೮ T.D U.D and S.G = U.G ೩೧೮ R.C = 'TEXT' and त.
> 20 and T.E = 25

2. What is meant by SQL injection? Illustrate with an example. (3)

2. a."In the recovery of concurrent transactions under the immediate database (4) modification
scheme, undo operations must be done before redo operations." Justify this statement with the
support of a small sample log.

lb. What is a cascade-less schedule? Give an example (4)

© Suppose that a task, which has been running in 2 hours, now runs
in 3.8 hours when (2) the system resources are doubled. Compute
the speed-up.

3. a. There are two relations R(A,B,C) and S(C,D,E) with the
following statistics: R (6) has 1,000 tuples of size 15 bytes
and R2 has 40,000 tuples of size 15 bytes. Estimate the number
of block transfers required using each of the following join
strategies for R*S assuming a block size of 300 bytes:-

1. Nested-loop join with 10 buffers

11. ii. Simple hash join with a uniform hash function (assume that the smaller
relation fits completely into memory)

Ignore the cost of result output.