1

GATE CSE 2006

MCQ (Single Correct Answer)

+1

-0.3

Which of the following relational query languages have the same expressive power?

I) Relational algebra

II) Tuple relational calculus restricted to safe expressions

III) Domain relational calculus restricted to safe expressions

2

GATE CSE 2005

MCQ (Single Correct Answer)

+1

-0.3

Let r be a relation instance with schema R = (A, B, C, D).

We define $${r_1} = {\pi _{A,B,C}}\left( r \right)$$ and $${r_1} = {\pi _{A,D}}\left( r \right)$$. Let $$s = {r_1}*{r_2}$$ where * denotes natural join. Given that the decomposition of r into r_{1}and r

_{2}is lossy, which one of the following is TRUE?

3

GATE CSE 2004

MCQ (Single Correct Answer)

+1

-0.3

Let R

_{1}(__A,__B, C) and R_{2}(__D,__E) be two relation schema, where the primary keys are shown underlined, and let C be a foreign key in R_{1}referring to R_{2}. Suppose there is no violation of the above referential integrity constraint in the corresponding relation instances r_{1}and r_{2}. Which one of the following relational algebra expressions would necessarily produce an empty relation?4

GATE CSE 2003

MCQ (Single Correct Answer)

+1

-0.3

Consider the following SQL query:

`Select distinct a`_{1}, a_{2}, ..., a_{n}
From r_{1}, r_{2}, ..., r_{m}
Where P;

For an arbitrary predicate P, this query is equivalent to which of the following relational algebra expressions? Questions Asked from Relational Algebra (Marks 1)

Number in Brackets after Paper Indicates No. of Questions

GATE CSE Subjects

Theory of Computation

Operating Systems

Algorithms

Database Management System

Data Structures

Computer Networks

Software Engineering

Compiler Design

Web Technologies

General Aptitude

Discrete Mathematics

Programming Languages