Question 1

An identifier serves the same role for a table that a key does for an entity.

Accepted Answer

A) True 
 B)False

Question 2

The principal difference between an entity and a table is that you can express a relationship between entities without using foreign keys.

Accepted Answer

A) True 
 B)False

Question 3

When designing a database,first identify the entities,then determine the attributes,and finally create the relationships.

Accepted Answer

A) True 
 B)False

Question 4

An entity instance is an occurrence of a particular entity.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following is not a good reason for designing a data model?

Accepted Answer

A)  It's easier to change things in the data model than it is in the actual DBMS.
B)  The data model provides a simplified view of the database that can be shown to people who don't need to see all the details.
C)  Creating a data model will help you understand the application area better.
D)  The data model can be discarded after the database is operational.

Question 6

In a minimum cardinality,minimums are generally stated as ________.

Accepted Answer

A)  0 or 1
B)  1 or N
C)  M or N
D)  one or many

Question 7

Distinguish between entity identifiers and keys.

Accepted Answer

An entity identifier is an attribute or ...

Question 8

A binary relationship is a relationship based on numerical entity instance identifiers.

Accepted Answer

A) True 
 B)False

Question 9

A composite attribute is an attribute that ________.

Accepted Answer

A)  is multivalued
B)  describes a characteristic of the relationship
C)  consists of a group of attributes
D)  is calculated at run-time

Question 10

A single relationship class involves only one entity class.

Accepted Answer

A) True 
 B)False

Question 11

For a relationship to be considered a binary relationship it must satisfy which of the following conditions?

Accepted Answer

A)  It must involve exactly two entity classes.
B)  It must have a maximum cardinality of 1:1.
C)  It must have a maximum cardinality of 1:N.
D)  Both A and B are correct

Question 12

Entities containing multivalued attributes are often represented using subtypes.

Accepted Answer

A) True 
 B)False

Question 13

An entity that represents something that can exist on its own is called a strong entity.

Accepted Answer

A) True 
 B)False

Question 14

In E-R modeling,entities within an entity class may have different attributes.

Accepted Answer

A) True 
 B)False

Question 15

A relationship's maximum cardinality indicates the maximum number of entities that can participate in the relationship.

Accepted Answer

A) True 
 B)False

Question 16

Which of the following is not true about subtype entities?

Accepted Answer

A)  Subtypes may be exclusive.
B)  The supertype and subtypes will have the same identifier.
C)  Subtypes are used to avoid a situation in which some attributes are required to be null.
D)  All subtypes of a supertype must have the same attributes.

Question 17

An identifier of an entity instance must consist of one and only one attribute.

Accepted Answer

A) True 
 B)False

Question 18

The degree of a relationship is expressed as the relationship's maximum cardinality.

Accepted Answer

A) True 
 B)False

Question 19

E-R models use an identifying relationship to connect entities that are ID-dependent.

Accepted Answer

A) True 
 B)False

Question 20

Relationships between supertypes and subtypes are called IS-A relationships.

Accepted Answer

A) True 
 B)False

Exam 5: Data Modeling With the Entity-Relationship Model

The principal difference between an entity and a table is that you can express a relationship between entities without using foreign keys.

Correct AnswerverifiedShow Answer

The degree of a relationship is expressed as the relationship's maximum cardinality.

Correct AnswerverifiedShow Answer

For a relationship to be considered a binary relationship it must satisfy which of the following conditions?

Correct AnswerverifiedShow Answer

E-R models use an identifying relationship to connect entities that are ID-dependent.

Correct AnswerverifiedShow Answer

An entity instance is an occurrence of a particular entity.

Correct AnswerverifiedShow Answer

In a minimum cardinality,minimums are generally stated as ________.

Correct AnswerverifiedShow Answer

Relationships between supertypes and subtypes are called IS-A relationships.

Correct AnswerverifiedShow Answer

Distinguish between entity identifiers and keys.

Correct AnswerverifiedAn entity identifier is an attribute or ...View AnswerShow Answer

An identifier of an entity instance must consist of one and only one attribute.

Correct AnswerverifiedShow Answer

Which of the following is not true about subtype entities?

Correct AnswerverifiedShow Answer

A binary relationship is a relationship based on numerical entity instance identifiers.

Correct AnswerverifiedShow Answer

A relationship's maximum cardinality indicates the maximum number of entities that can participate in the relationship.

Correct AnswerverifiedShow Answer

In E-R modeling,entities within an entity class may have different attributes.

Correct AnswerverifiedShow Answer

Which of the following is not a good reason for designing a data model?

Correct AnswerverifiedShow Answer

When designing a database,first identify the entities,then determine the attributes,and finally create the relationships.

Correct AnswerverifiedShow Answer

A single relationship class involves only one entity class.

Correct AnswerverifiedShow Answer

An identifier serves the same role for a table that a key does for an entity.

Correct AnswerverifiedShow Answer

An entity that represents something that can exist on its own is called a strong entity.

Correct AnswerverifiedShow Answer

Entities containing multivalued attributes are often represented using subtypes.

Correct AnswerverifiedShow Answer

A composite attribute is an attribute that ________.

Correct AnswerverifiedShow Answer

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An entity identifier is an attribute or ...
View Answer

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