Database Management Systems (3130703) MCQs

MCQs of Relational Query Languages

Showing 31 to 30 out of 40 Questions
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31.

If T1 and T2 are two relations, then which of the following is not a valid relational algebra expression ?

(a)

T1 - T2
(b)

T1 ∪ T2
(c)

T1 ∩ T2
(d)

All are valid expressions
Answer:

Option (d)

32.

Relational algebra is :

(a)

Data Definition Language
(b)

Meta Language
(c)

Procedural query language
(d)

Binary language
Answer:

Option (c)

33.

Cartesian product in relational algebra is

(a)

a Unary operator
(b)

a Binary operator
(c)

a Ternary operator
(d)

not defined
Answer:

Option (b)

34.

_______ produces the relation that has attributes of R1 and R2.

(a)

Cartesian product
(b)

Difference
(c)

Intersection
(d)

Division
Answer:

Option (a)

35.

Which of the following operation is used if we are interested in only certain columns of a table?

(a)

PROJECTION
(b)

SELECTION
(c)

UNION
(d)

JOIN
Answer:

Option (a)

36.

Using Relational Algebra the query that finds customers, who have a balance of over 1000 is

(a)

Π Customer_name(σ balance >1000(Deposit))
(b)

σ Customer_name(Π balance >1000(Deposit))
(c)

Π Customer_name(σ balance >1000(Borrow))
(d)

σ Customer_name(Π balance >1000(Borrow))
Answer:

Option (a)

37.

If in the JOIN operation, the conditions of JOIN operation are not satisfied then the results of the operation is

(a)

0
(b)

1
(c)

2
(d)

3
Answer:

Option (a)

38.

The DIVISION operation can be applied to two relations A and B such as R(A)  ÷  R(B) where as

(a)

A does not belong to B
(b)

A must be added to B
(c)

A belongs or equal to B
(d)

A must be subtracted from B
Answer:

Option (c)

39.

The JOIN operator can be specified as :

(a)

R X S
(b)

σ (condition) R U S
(c)

σ (condition) R X S
(d)

σ (condition) R - S
Answer:

Option (c)

40.

In the output of Cross Product:

Attributes of Resultant Relation =  ______________

(a)

Attributes of Relation R1 * Attributes of Relation R2
(b)

Attributes of Relation R1 + Attributes of Relation R2
(c)

Attributes of Relation R1 - Attributes of Relation R2
(d)

Attributes of Relation R2 - Attributes of Relation R1
Answer:

Option (b)

Showing 31 to 30 out of 40 Questions
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