GATE CSE 2024 Set 1 | Functional Dependencies and Normalization Question 3 | Database Management System

GATE CSE 2024 Set 1

MCQ (More than One Correct Answer)

-0.66

The symbol → indicates functional dependency in the context of a relational database. Which of the following options is/are TRUE?

(X, Y) → (Z, W) implies X → (Z, W)

(X, Y) → (Z, W) implies (X, Y) → Z

((X, Y) → Z and W → Y) implies (X, W) → Z

(X → Y and Y → Z) implies X → Z

GATE CSE 2021 Set 1

MCQ (Single Correct Answer)

-0.67

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

PQ → X; P → YX; Q → Y; Y → 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?

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

Both D₁ and D₂ are lossless decompositions.

Both D₁ and D₂ are lossy decompositions.

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

GATE CSE 2020

MCQ (Single Correct Answer)

-0.67

Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE?

A cell in R holds a set instead of an atomic value.

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

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.

R has a nontrivial functional dependency X $$ \to $$ A, where X is not a superkey and A is a prime attribute.

GATE CSE 2019

MCQ (Single Correct Answer)

-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?

I only

Neither I nor II

II only

Both I and II

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