1
GATE CSE 2010
MCQ (Single Correct Answer)
+2
-0.6
The following functional dependencies hold for relations R(A, B, C) and S(B, D, E): $$$\eqalign{ & B \to A \cr & A \to C \cr} $$$

The relation R contains 200 tuples and the relation S contains 100 tuples. What is the maximum number of tuples possible in the natural join R $$\Join$$ S?

A
100
B
200
C
300
D
2000
2
GATE CSE 2008
MCQ (Single Correct Answer)
+2
-0.6
Let R and S be two relations with the following schema

R (P, Q, R1, R2, R3)

S (P, Q, S1, S2)

Where {P, Q} is the key for both schemas. Which of the following queries are equivalent?
I. $$\Pi_P \left(R \bowtie S\right)$$
II. $$\Pi_P \left(R\right) \bowtie \Pi_P\left(S\right)$$
III. $$\Pi_P \left(\Pi_{P, Q} \left(R\right) \cap \Pi_{P,Q} \left(S\right) \right)$$
IV. $$\Pi_P \left(\Pi_{P, Q} \left(R\right) - \left(\Pi_{P,Q} \left(R\right) - \Pi_{P,Q} \left(S\right)\right)\right)$$
A
Only I and II
B
Only I and III
C
Only I, II and III
D
Only I, III and IV
3
GATE CSE 2007
MCQ (Single Correct Answer)
+2
-0.6
Consider a selection of the form σA ≤ 100(r), where r is a relation with 1000 tuples. Assume that the attribute values for A among the tuples are uniformly distributed in the interval [ 0, 500 ]. Which one of the following options is the best estimate of the number of tuples returned by the given selection query?
A
50
B
100
C
150
D
200
4
GATE CSE 2007
MCQ (Single Correct Answer)
+2
-0.6

Information about a collection of students is given by the relation studInfo(studId, name, sex). The relation enroll(studId, courseId) gives which student has enrolled for (or taken) what course(s). Assume that every course is taken by at least one male and at least one female student. What does the following relational algebra expression represent?

$$\eqalign{ & \prod\nolimits_{courseId} {((\prod\nolimits_{studId} {({\sigma _{sex = 'female'}}} } \cr & (studInfo)) \times \prod\nolimits_{courseId} {(enroll)) - enroll)} \cr} $$
A
Courses in which all the female students are enrolled.
B
Courses in which a proper subset of female students are enrolled.
C
Courses in which only male students are enrolled.
D
None of the above.
GATE CSE Subjects
Software Engineering
Web Technologies
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
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CBSE
Class 12