Database Management System
Er Diagrams
Marks 1Marks 2
Functional Dependencies and Normalization
Marks 1Marks 2
Structured Query Language
Marks 1Marks 2
Relational Algebra
Marks 1Marks 2
Transactions and Concurrency
Marks 1Marks 2
File Structures and Indexing
Marks 1Marks 2
1
GATE CSE 2021 Set 1
MCQ (Single Correct Answer)
+2
-0.67

Consider the relation R(P, Q, S, T, X, Y, Z, W) with the following functional dependencies.

PQ â†’ X; P â†’ YX; Q â†’ Y; Y â†’ ZW

Consider the decomposition of the relation R into the constituent relations according to the following two decomposition schemes.

D1 : R = [(P, Q, S, T); (P, T, X); (Q, Y); (Y, Z, W)]

D2 : R = [(P, Q, S); (T, X); (Q, Y); (Y, Z, W)]

Which one of the following options is correct?

A

D1 is a lossy decomposition, but D2 is a lossless decomposition.

B
Both D1 and D2 are lossless decompositions.
C
Both D1 and D2 are lossy decompositions.
D
D1 is a lossless decomposition, but D2 is a lossy decomposition.
2
GATE CSE 2020
MCQ (Single Correct Answer)
+2
-0.67
Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE?
A
A cell in R holds a set instead of an atomic value.
B
R has a nontrivial functional dependency X $$ \to $$ A, where X is not a superkey and A is a non-prime attribute and X is not a proper subset of any key
C
R has a nontrivial functional dependency X $$ \to $$ A, where X is not a superkey and A is a non-prime attribute and X is a proper subset of some key.
D
R has a nontrivial functional dependency X $$ \to $$ A, where X is not a superkey and A is a prime attribute.
3
GATE CSE 2019
MCQ (Single Correct Answer)
+2
-0.67
Let the set of functional dependencies

F = {QR → S, R → P, S → Q}

hold on a relation schema X = (PQRS). X is not in BCNF. Suppose X is decomposed into two schemas Y and Z, where Y = (PR) and Z = (QRS).

Consider the two statements given below.

I. Both Y and Z are in BCNF
II. Decomposition of X into Y and Z is dependency preserving and lossless

Which of the above statements is/are correct?
A
I only
B
Neither I nor II
C
II only
D
Both I and II
4
GATE CSE 2015 Set 1
Numerical
+2
-0

Consider an Entity-Relationship (ER) model in which entity sets E1 and E2 are connected by an m : n relationship R12. E1 and E3 are connected by a 1 : n (1 on the side of E1 and n on the side of E3) relationship R13.

E1 has two single-valued attributes a11 and a12 of which a11 is the key attribute. E2 has two single-valued attributes a21 and a22 of which a21 is the key attribute. E3 has two single-valued attributes a31 and a32 of which a31 is the key attribute. The relationships do not have any attributes.

If a relational model is derived from the above ER model, then the minimum number of relations that would be generated if all the relations are in 3NF is _______.

Your input ____
GATE CSE Subjects
Theory of Computation
Operating Systems
Algorithms
Digital Logic
Database Management System
Data Structures
Computer Networks
Software Engineering
Compiler Design
Web Technologies
General Aptitude
Discrete Mathematics
Programming Languages
Computer Organization