Module 2

Question 2

Is it true that end users find it difficult to think of a relation as a table?

Answer 2

True

Question 3

It is perceived as a two-dimensional structure composed of rows and columns. What is this structure called?

Answer 3

Table

Question 4

E. F. Codd used the terms ‘relation’ and ________ as synonyms.

Answer 4

Table

Question 5

You can think of a table as a persistent representation of a logical relation— that is, a ________ whose contents can be permanently saved for future use.

Answer 5

Relation

Question 6

A table that contains a group of related entity occurrences is called an ________.

Answer 6

Entity Set

Question 7

In the relational model, ______ is/are important because they are used to ensure that each row in a table is uniquely identifiable.

Answer 7

Keys

Question 8

A ________ consists of one or more attributes that determine other attributes.

Answer 8

Key

Question 9

The relationship is called ___________, which means that the value of one or more attributes determines the value of one or more other attributes.

Answer 9

Functional Dependence

Question 10

The attribute whose value determines another is called a ________.

Answer 10

Determinant

Question 11

The attribute whose value is determined by the other attribute is called ________.

Answer 11

Dependent

Question 12

A table is perceived as a two-dimensional structure composed of rows and columns. Is this statement true?

Answer 12

True

Question 13

Can a table row (tuple) represent multiple entities at the same time?

Answer 13

False

Question 14

Each table column represents an attribute, and each column has a distinct name. Is this statement true?

Answer 14

True

Question 15

Each intersection of a row and column represents a multiple data value. Is this statement true?

Answer 15

False

Question 16

All values in a column must conform to the same data format. Is this statement true?

Answer 16

True

Question 17

Each column has a specific range of values known as the ________.

Answer 17

Attribute domain

Question 18

The order of the rows and columns is immaterial to the DBMS. Is this statement true?

Answer 18

True

Question 19

Which of the following statements about Entity Integrity and Referential Integrity is TRUE?

Answer 19

A Foreign Key (FK) must always reference an existing Primary Key value or be null.

Question 20

What best describes Entity Integrity?

Answer 20

A Primary Key ensures each row has a unique identity and cannot be null.

Question 21

What best describes the Referential Integrity Rule?

Answer 21

A Foreign Key must reference an existing Primary Key value or be null.

Question 22

One of the set operators that is referred to as a unary operator because it only uses one table as input is ________.

Answer 22

Select

Question 23

One of the set operators that yields all values for selected attributes is called ________.

Answer 23

Project

Question 24

One of the set operators that combines all rows from two tables, excluding duplicate rows is called ________.

Answer 24

Union

Question 25

One of the set operators that yields only the rows that appear in both tables is called ________.

Answer 25

Intersect

Question 26

One of the set operators that yields all rows in one table that are not found in the other table is called ________.

Answer 26

Difference

Question 27

One of the set operators that yields all possible pairs of rows from two tables is called ________.

Answer 27

Product

Question 28

One of the set operators that allows information to be intelligently combined from two or more tables is called ________.

Answer 28

Join

Question 29

One of the set operators that links tables by selecting only the rows with common values in their common attribute(s) is called ________.

Answer 29

Natural Join

Question 30

It provides a detailed description of all tables in the database created by the user and designer. What is this called?

Answer 30

Data Dictionary

Question 31

This relationship is the norm for relational databases. What is it?

Answer 31

1:M

Question 32

This relationship can be related to only one other entity, and vice versa. What is it?

Answer 32

1:1

Question 33

This relationship is not supported directly in the relational environment. What is it?

Answer 33

M:N

Question 34

This is a detailed, logical representation of the data for an organization or for a business area. What is it called?

Answer 34

entity-relationship model

Question 35

Who first introduced the ER data model and in what year?

Answer 35

Peter Chen_1976

Question 36

It was defined as anything about which data will be collected and stored. What is this?

Answer 36

Entity

Question 37

Each entity consists of a set of attributes that describes particular characteristics of the entity. Is this statement true?

Answer 37

True

Question 38

The ERM uses _______—one or more attributes that uniquely identify each entity instance.

Answer 38

Identifiers

Question 39

An attribute that can have only a single value is called ________.

Answer 39

Single-valued attributes

Question 40

These are attributes that can have many values. What are they called?

Answer 40

Multivalued Attributes

Question 41

An attribute whose value is calculated from other attributes is called ________.

Answer 41

Derived Attribute

Question 42

What describes associations among data?

Answer 42

Relationships

Question 43

What is used to describe the relationship classification?

Answer 43

connectivity

Question 44

It expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity. What is this called?

Answer 44

Cardinality

Question 45

It indicates the number of entities or participants associated with a relationship. What is this called?

Answer 45

Relationship Degree

Question 46

What exists when an association is maintained within a single entity?

Answer 46

unary relationship

Question 47

What exists when two entities are associated?

Answer 47

binary relationship

Question 48

What exists when three entities are associated?

Answer 48

ternary relationship