Database Systems Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the correct terminology for the components of a relation?

Entity, instance, value

Table, row, column

Relation, tuple, attribute (correct)

Set, element, property

What is a key characteristic of a relation in a database?

Tuples are distinct; there are no duplicates (correct)

The order of attributes has significance

Tuples can have duplicate values

Attributes can have duplicate names

What is a super key in the context of database systems?

A set of attributes that uniquely identifies a tuple within a relation (correct)

The primary key of a relation

An attribute that uniquely identifies a relation

A foreign key referencing another relation

What is true about a candidate key in a database system?

It is a super key with no proper subset being a super key Signup and view all the answers

What is a composite key in a database system?

A key consisting of more than one attribute Signup and view all the answers

What does a foreign key represent in a database system?

An attribute that matches the primary key of another relation Signup and view all the answers

What does the entity integrity constraint state in a database system?

No attribute of a primary key can be null Signup and view all the answers

What is a base relation in a database system?

A named relation stored in the database Signup and view all the answers

What represents a physically stored relation in the database?

Relation Signup and view all the answers

What is represented by an entity type in the ER model?

A relationship between objects Signup and view all the answers

What is a relationship type in the ER model?

A set of meaningful associations among entity types Signup and view all the answers

What is an attribute in the ER model?

A property of an entity or a relationship type Signup and view all the answers

What is the difference between a composite attribute and a simple attribute?

Composite attributes can be divided into smaller subparts; simple attributes cannot Signup and view all the answers

What is a multivalued attribute?

An attribute that can have multiple values for each entity Signup and view all the answers

What is a derived attribute?

An attribute that is calculated from other attributes Signup and view all the answers

What does a value set or domain represent for an attribute?

The set of all possible values for an attribute Signup and view all the answers

Study Notes

Database Systems: Components and Terminology

A relation consists of tuples (rows) and attributes (columns)
Correct terminology: relation, tuple, attribute
Attributes can have distinct names, but no duplicates

Properties of Relations

Each cell contains exactly one atomic value
Tuples are distinct, no duplicates
The order of attributes has no significance

Keys

A super key is a set of attributes that uniquely identifies a tuple within a relation
A candidate key is a super key with no proper subset being a super key
A primary key is a selected candidate key for each relation
A composite key consists of more than one attribute

Foreign Keys

A foreign key represents an attribute that matches the primary key of another relation
Foreign keys must match a candidate key value or be null

Entity Integrity Constraint

No attribute of a primary key can be null

Base Relations and Views

A base relation is a named relation stored in the database
A view is a dynamic result of relational operations on base relations

ER Model: Entity Types, Relationships, and Attributes

An entity type represents a group of objects with the same properties
A relationship type represents a set of meaningful associations among entity types
An attribute is a property of an entity or a relationship type

Attributes in ER Model

A composite attribute can be divided into smaller subparts
A multivalued attribute can have multiple values for each entity
A derived attribute is calculated from other attributes
A value set or domain represents the set of all possible values for an attribute

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Assess your knowledge of database systems with these 40 multiple-choice questions covering topics such as relations, attributes, and tuples. Test your understanding of database fundamentals and concepts.