DBMS Multiple choice Questions and Answers-UGC NET computer science question paper

1.	Which of the following is true ?
a.	A relation in BCNF is always in 3NF
b.	A relation in 3NF is always in BCNF
c.	BCNF and 3NF are same
d.	A relation in BCNF is not in 3NF

Discuss

Answer: (a).A relation in BCNF is always in 3NF

2.	In DML, RECONNECT command cannot be used with
a.	OPTIONAL Set
b.	FIXED Set
c.	MANDATOR Set
d.	All of the above

Discuss

Answer: (b).FIXED Set

3.	A hash function f defined as f (key) = key mod 13, with linear probing is used to insert keys 55, 58, 68, 91, 27, 145. What will be the location of 79 ?
a.	2
b.	3
c.	4
d.	5

Discuss

Answer: (d).5

4.	The User Work Area (UWA) is a set of Program variables declared in the host program to communicate the contents of individual records between
a.	DBMS & the Host record
b.	Host program and Host record
c.	Host program and DBMS
d.	Host program and Host language

Discuss

Answer: (c).Host program and DBMS

5.	Given a Relation POSITION (Posting-No, Skill), then query to retrieve all distinct pairs of posting-nos requiring skill is
a.	Select p.posting-No, p.posting-No from position p where p.skill = p.skill and p.posting-No < p.posting-No
b.	Select p1.posting-No, p2.posting-No from position p1, position p2 where p1.skill = p2.skill
c.	Select p1.posting-No, p2.posting-No from position p1, position p2 where p1.skill = p2.skill and p1.posting-No < p2.posting-No
d.	Select p1.posting-No, p2.posting-No from position p1, position p2 where p1.skill = p2.skill and p1.posting-No = p2.posting.No

Discuss

Answer: (c).Select p1.posting-No, p2.posting-No from position p1, position p2 where p1.skill = p2.skill and p1.posting-No < p2.posting-No

6.	If a relation with a Schema R is decomposed into two relations R1 and R2 such that (R1 ∪ R2) = R1 then which one of the following is to be satisfied for a lossless joint decomposition (---> indicates functional dependency)
a.	(R1 ∩ R2) --> R1 or R1 ∩ R2 ---> R2
b.	R1 ∩ R2 --> R1
c.	R1∩ R2 --> R2
d.	R1 ∩ R2 --> R1 and R1 ∩ R2 --> R2

Discuss

Answer: (a).(R1 ∩ R2) --> R1 or R1 ∩ R2 ---> R2

7.	Which level of Abstraction describes how data are stored in the data base ?
a.	Physical level
b.	View level
c.	Abstraction level
d.	Logical level

Discuss

Answer: (a).Physical level

8.	Third normal form is based on the concept of ______.
a.	Closure Dependency
b.	Transitive Dependency
c.	Normal Dependency
d.	Functional Dependency

Discuss

Answer: (b).Transitive Dependency

9.	The student. marks should not be greater than 100. This is
a.	Integrity constraint
b.	Referential constraint
c.	Overdefined constraint
d.	Feasible constraint

Discuss

Answer: (a).Integrity constraint

10.	GO BOTTOM and SKIP-3 commands are given one after another in a database file of 30 records. It shifts the control to
a.	28th record
b.	27th record
c.	3rd record
d.	4th record

Discuss

Answer: (b).27th record