Database Questions and Answers – Relational Algebra

This set of Database Questions & Answers focuses on “Relational Algebra”

1. Relational Algebra is a __________ query language that takes two relation as input and produces another relation as output of the query.
a) Relational
b) Structural
c) Procedural
d) Fundamental
View Answer

Answer:c
Explanation:This language has fundamental and other operations which are used on relations .

2. Which of the following is a fundamental operation in relational algebra ?
a) Set intersection
b) Natural join
c) Assignment
d) None of the mentioned
View Answer

Answer:d
Explanation:The fundamental operations are select, project, union, set difference, Cartesian product, and rename.

3. 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)
View Answer

Answer:b
Explanation:The select operation selects tuples that satisfy a given predicate.

4. 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
View Answer

Answer:a
Explanation:None.

5. 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
View Answer

Answer:b
Explanation:The expression r − s produces a relation containing those tuples in r but not in s.

6. Which is a unary operation:
a) Selection operation
b) Primitive operation
c) Projection operation
d) Generalized selection
View Answer

Answer:d
Explanation:Generalization Selection takes only one argument for operation.

7. Which is a join condition contains an equality operator:
a) Equijoins
b) Cartesian
c) Natural
d) Left
View Answer

Answer:a
Explanation:None.

8. In precedence of set operators the expression is evaluated from
a) Left to left
b) Left to right
c) Right to left
d) From user specification
View Answer

Answer:b
Explanation:The expression is evaluated from left to right according to the precedence.

9. Which of the following is not outer join ?
a) Left outer join
b) Right outer join
c) Full outer join
d) All of the mentioned
View Answer

Answer:d
Explanation:The FULL OUTER JOIN keyword combines the result of both LEFT and RIGHT joins.

10. The assignment operator is denoted by
a) ->
b) <-
c) =
d) ==
View Answer

Answer:b
Explanation:the result of the expression to the right of the ← is assigned to the relation variable on the left of the ←.

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Manish Bhojasia, a technology veteran with 17+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer and SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage & Cluster Administration, Advanced C Programming, SAN Storage Technologies, SCSI Internals and Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him below.


Sanfoundry Training Center of Excellence (CoE)

Manish Bhojasia, a technology veteran with 17+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer and SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage & Cluster Administration, Advanced C Programming, SAN Storage Technologies, SCSI Internals and Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him below.







1000 DBMS MCQs | Quiz

Relational Database and Database Schema
Keys
Relational Query Operations and Relational Operators
SQL Basics and SQL Data Definition
SQL Queries
Basic SQL Operations
Set Operations
Null Values Operations
Aggregate Functions and Nested Subqueries 1
Aggregate Functions and Nested Subqueries 2
Modification of Database
Join Expressions
Views
Transactions
Integrity Constraints
SQL Data Types and Schemas
Authorizations
Access SQL From a Programming Language
Functions and Procedures
Triggers
Recursive Queries and Aggregation Features
OLAP
Relational Algebra
Tuple Relational Calculus and Domain Relational Calculus
The Entity-Relationship Model
Constraints
Entity-Relationship Diagrams
Reduction to Relational Schemas
Entity-Relationship Design Issues
Extended E-R Features
Querying database part-1 DDL
Querying database part-2 DML
Atomic Domains
Normal Forms
Functional-Dependency Theory
Algorithms for Decomposition
Multivalued Dependencies
Database Design Process
Application Programs and User Interfaces
Web Fundamentals
Servlets and JSP
Application Architectures
Rapid Application Development
Application Performance
Application Security
Encryption and Its Applications
Physical Storage Media
Magnetic Disk and Flash Storage
RAID
Tertiary Storage
File Organisations
Organization of Records in Files
Data-Dictionary Storage
Database Buffer
Ordered Indices
Hashing Techniques
Ordered Indexing and Hashing
Bitmap Indices
Index Definition in SQL
Query Processing
Selection Operation
Sorting
Join Operations
Evaluation of Expressions
Transformation of Relational Expressions
Estimating Statistics of Expression Results
Materialized Views
Advanced Query Optimization
Transaction Concept
A Simple Transaction Model
Storage Structure
Transaction Atomicity and Durability
Querying database part 3
Querying database part 4
Querying database part 5
Implementation of Isolation Levels
Transactions as SQL Statements
Lock-Based Protocols
Deadlocks
Multiple Granularity
Multiversion Schemes
Snapshot Isolation
Insertion Deletion Predicate Reads
Concurrency in Index Structures
Failure Classification
Recovery
Buffer Management
Failure with Nonvolatile Storage
ARIES
Lock Release and Undo Operations
Remote Backup Systems
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