1
GATE CSE 2006
MCQ (Single Correct Answer)
+2
-0.6
Consider the relation enrolled (student, course) in which (student, course ) is the primary key, and the relation Paid (student, amount) where student is the primary key. Assume no null values and no foreign keys or integrity constraints. Assume that amounts $$6000, 7000, 8000,9000$$ and $$10000$$ were each paid by $$20$$% of the students. Consider these query plans (Plan $$1$$ on left, Plan $$2$$ on right) to ''List all courses taken by students who have paid more than $$x''$$. GATE CSE 2006 Database Management System - Functional Dependencies and Normalization Question 17 English 1 GATE CSE 2006 Database Management System - Functional Dependencies and Normalization Question 17 English 2

A disk seek takes $$4ms$$, disk data transfer bandwidth is $$300MB/s$$ and checking a tuple to see if amount is greater than $$x$$ takes $$10\mu s.$$ Which of the following statements is correct?

A
Plan $$1$$ and Plan $$2$$ will not output identical row sets for all databases
B
A course may be listed more than once in the output of plan $$1$$ for some databases
C
For $$x=5000,$$ Plan $$1$$ executes faster than plan $$2$$ for all databases
D
For $$x=9000,$$ Plan $$1$$ executes slower than plan $$2$$ for all databases
2
GATE CSE 2006
MCQ (Single Correct Answer)
+2
-0.6
The following functional dependencies are given :
$$\eqalign{ & AB \to CD,\,AF \to D,\,\,DE \to F, \cr & C \to G.\,\,\,\,\,\,\,\,\,\,F \to E.\,\,\,\,\,\,\,\,\,G \to A. \cr} $$

Which one of the following options is false?

A
$${\left\{ {CF} \right\}^ + }\,\,\, = \left\{ {ACDEFG} \right\}$$
B
$${\left\{ {BG} \right\}^ + }\,\, = \left\{ {ABCDG} \right\}$$
C
$${\left\{ {AF} \right\}^ + }\,\, = \left\{ {ACDEFG} \right\}$$
D
$${\left\{ {AB} \right\}^ + }\,\, = \left\{ {ABCDG} \right\}$$
3
GATE CSE 2005
MCQ (Single Correct Answer)
+2
-0.6
In a schema with attributes $$A, B, C, D,$$ and $$E,$$ following set of functional dependencies are given
$$\eqalign{ & \,\,\,A \to B \cr & \,\,\,A \to C \cr & CD \to E \cr & \,\,\,B \to D \cr & \,\,\,E \to A \cr} $$

Which of the following functional dependencies is NOT implied by the above set?

A
$$CD \to AC$$
B
$$BD \to CD$$
C
$$BC \to CD$$
D
$$AC \to BC$$
4
GATE CSE 2005
MCQ (Single Correct Answer)
+2
-0.6
Consider a relation scheme $$R = \left( {A,\,B,\,C,\,D,\,E,\,H} \right)$$ on which the following functional dependencies hold: $$\left\{ {A \to B,\,\,BC \to D,\,\,E \to C,\,\,D \to A} \right\}.$$ What are the candidate keys of $$R?$$
A
$$AE, BE$$
B
$$AE, BE, DE$$
C
$$AEH, BEH, BCH$$
D
$$AEH, BEH, DEH$$
GATE CSE Subjects
Software Engineering
Web Technologies
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
CBSE
Class 12