Database Management Systems (3130703) MCQs

MCQs of Relational Query Languages

Showing 21 to 30 out of 40 Questions
1 2 3 4
21.

A primary key is combined with a foreign key creates

(a)

Parent-Child relation ship between the tables that connect them.
(b)

Many to many relationship between the tables that connect them.
(c)

Network model between the tables that connect them.
(d)

Binary model between the tables that connect them.
Answer:

Option (a)

22.

An instance of relational schema R (A, B, C) has distinct values of A. Which one of the following is true?

(a)

A is a primary Key
(b)

A is a foreign Key
(c)

A is a alternate Key
(d)

A is a check Key
Answer:

Option (a)

23.

Consider the join of a relation R with relation S. If R has m tuples and S has n tuples, then the maximum size of join is

(a)

mn
(b)

m+n
(c)

(m+n)/2
(d)

2(m+n)
Answer:

Option (a)

24.

A database object that holds a collection of data for a specific topic is called _________

(a)

Row
(b)

Table
(c)

Column
(d)

Database
Answer:

Option (b)

25.

______________ is a set of all possible unique values for a specific column.

(a)

Row
(b)

Column
(c)

Domain
(d)

Table
Answer:

Option (c)

26.

Which of the following is used to denote the selection operation in relational algebra?

(a)

Pi (Greek)
(b)

Sigma (Greek)
(c)

Lambda (Greek)
(d)

Omega (Greek)
Answer:

Option (b)

27.

For select operation the ________ appear in the subscript and the ___________ argument appears in the paranthesis after the sigma.

(a)

Predicates, relation
(b)

Relation, Predicates
(c)

Operation, Predicates
(d)

Relation, Operation
Answer:

Option (a)

28.

The ___________ operation, denoted by -, allows us to find tuples that are in one relation but are not in another.

(a)

Union
(b)

Set-difference
(c)

Difference
(d)

Intersection
Answer:

Option (b)

29.

 If E1 and E2 are relational algebra expressions, then which of the following is NOT a relational algebra expression?

(a)

E1 ∪ E2
(b)

E1 / E2
(c)

E1 - E2
(d)

E1 x E2
Answer:

Option (b)

30.

The operation of a relation X, produces Y, such that Y contains only selected attributes of X. Such an operation is:

(a)

Projection
(b)

Intersection
(c)

Union
(d)

Difference
Answer:

Option (a)

Showing 21 to 30 out of 40 Questions
1 2 3 4