1
Which one of the following is a procedural language?
Correct Answer
Relational algebra
โ MCQ PRACTICE
Database Management Systems Unit 2
Practice objective questions for quick revision and examination preparation. Try answering each question before revealing the answer.
Database Management Systems - Unit-2
2
The_____ operation allows the combining of two relations by merging pairs of tuples, one from each relation, into a single tuple.
Correct Answer
Join
3
The result which operation contains all pairs of tuples from the two relations, regardless of whether their attribute values match.
Correct Answer
Cartesian product
4
The _______ operator takes the results of two queries and returns only rows that appear in both result sets.
Correct Answer
Intersect
5
The _________ provides a set of operations that take one or more relations as input and return a relation as an output.
Correct Answer
Relational algebra
6
Relational Algebra is a __________ query language that takes two relations as input and produces another relation as an output of the query.
Correct Answer
Procedural
7
Which of the following is used to denote the selection operation in relational algebra?
Correct Answer
Sigma (Greek)
8
For select operation the ________ appear in the subscript and the ___________ argument appears in the parenthesis after the sigma.
Correct Answer
Predicates, relation
9
Find the ID, name, dept name, salary for instructors whose salary is greater than $80,000 .
Correct Answer
{t | t ฮต instructor โง t[salary] > 80000}
10
A query in the tuple relational calculus is expressed as:
Correct Answer
{t | P(t)}
11
An expression in the domain relational calculus is of the form
Correct Answer
{< x1, x2, . . . , xn > | P(x1, x2, . . . , xn)}
12
In domain relational calculus โthere existโ can be expressed as
Correct Answer
ะญ x (P1(x))
13
Which of the following creates a virtual relation for storing the query?
Correct Answer
View
14
Which of the following is the syntax for views where v is view name?
Correct Answer
Create view v as โquery expressionโ;
15
Updating the value of the view
Correct Answer
Will affect the relation from which it is defined
16
SQL view is said to be updatable (that is, inserts, updates or deletes can be applied on the view) if which of the following conditions are satisfied by the query defining the view?
Correct Answer
All of the mentioned
17
Drop Table cannot be used to drop a table referenced by a _________ constraint.
Correct Answer
Foreign Key
18
______ is a special type of integrity constraint that relates two relations & maintains consistency across the relations.
Correct Answer
Referential Integrity Constraints
19
An entity in A is associated with at most one entity in B, and an entity in B is associated with at most one entity in A.This is called as
Correct Answer
One-to-one
20
A Key which is a set of one or more columns that can identify a record uniquely is called?
Correct Answer
Candidate key
21
Relational Algebra does not have
Correct Answer
Aggregation operators
22
If two relations R and S are joined, then the non matching tuples of both R and S are ignored in
Correct Answer
inner join
23
The common column is eliminated in
Correct Answer
natural join
24
Relational calculus is a
Correct Answer
Declarative Language
25
_______ produces the relation that has attributes of R1 and R2
Correct Answer
Cartesian product
26
The following conditions must be met by a union operation.
Correct Answer
Both A. and B.