Question 1

Explain the ambiguity in the broad definition of a weak entity.

Accepted Answer

The broad definition of a weak entity includes any entity that relies on another entity for its existence in the database.This is ambiguous since this definition can apply to any entity that is involved in a relationship with a minimum cardinality of 1.If the minimum cardinality is 1,then an entity instance in that entity class cannot exist in the database unless there is a related entity instance in the associated entity class.The more restrictive definition of a weak entity indicates that an entity is weak if it logically depends on the other entity for its existence.

Question 2

Entities can be associated with one another in relationships.

Accepted Answer

A) True 
 B)False  True

Question 3

Subtype entities contain only attributes unique to the subtypes.

Accepted Answer

A) True 
 B)False  True

Question 4

To represent an archetype/instance pattern in an E-R model,________.

Accepted Answer

A) create a new ID-dependent entity with a 1:N relationship 
B) create a new weak,but not ID-dependent entity with a 1:N relationship 
C) create a new strong entity with a 1:1 relationship 
D) create a new ID-dependent entity with a 1:1 relationship 
E) create a new weak,but not ID-dependent entity with a 1:1 relationship 
A) create a new ID-dependent entity with a 1:N relationship 
B) create a new weak,but not ID-dependent entity with a 1:N relationship 
C) create a new strong entity with a 1:1 relationship 
D) create a new ID-dependent entity with a 1:1 relationship 
E) create a new weak,but not ID-dependent entity with a 1:1 relationship

Question 5

The supremetype entity contains the attributes that are common to all subtypes.

Accepted Answer

A) True 
 B)False

Question 6

Common variants of the E-R model include:

Accepted Answer

A) IE Crow's Foot 
B) IDEF1X 
C) UML 
D) A and B 
E) A,B and C 
A) IE Crow's Foot 
B) IDEF1X 
C) UML 
D) A and B 
E) A,B and C

Question 7

Distinguish between entity identifiers and keys.

Accepted Answer

An entity identifier is an attribute or

Question 8

An entity is something that users want to track.

Accepted Answer

A) True 
 B)False

Question 9

Recursive relationships only exist for one-to-one relationships.

Accepted Answer

A) True 
 B)False

Question 10

Relationships among instances of a single entity class are called redundant relationships.

Accepted Answer

A) True 
 B)False

Question 11

-You are given an E-R diagram with two entities,ORDER and CUSTOMER,as shown above.What does the symbol next to the ORDER entity indicate?

Accepted Answer

A) A maximum cardinality of "zero" 
B) A maximum cardinality of "one" 
C) A minimum cardinality of "optional" 
D) A minimum cardinality of "required" 
E) None of the above. 
A) A maximum cardinality of "zero" 
B) A maximum cardinality of "one" 
C) A minimum cardinality of "optional" 
D) A minimum cardinality of "required" 
E) None of the above.

Question 12

An identifier may be ________.

Accepted Answer

A) composite 
B) a single attribute 
C) a relationship 
D) A and B 
E) A,B and C 
A) composite 
B) a single attribute 
C) a relationship 
D) A and B 
E) A,B and C

Question 13

An entity whose identifier includes the identifier of another entity is a(n)________.

Accepted Answer

A) strong entity 
B) weak entity 
C) ID-dependent entity 
D) A and C 
E) B and C 
A) strong entity 
B) weak entity 
C) ID-dependent entity 
D) A and C 
E) B and C

Question 14

Which of the following is considered to be a weak entity?

Accepted Answer

A) ID-dependent entity 
B) subtype entity 
C) association entity 
D) B and C 
E) A,B and C 
A) ID-dependent entity 
B) subtype entity 
C) association entity 
D) B and C 
E) A,B and C

Question 15

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

Accepted Answer

A) True 
 B)False

Question 16

-You are given an E-R diagram with two entities,ORDER and CUSTOMER,as shown above,and are asked to draw the relationship between them.If a given customer can place many orders and a given order can be by one or more customers,which of the following should be indicated in the relationship symbol between the two entities?

Accepted Answer

A) 0:1 
B) 1:1 
C) 1:N 
D) N:1 
E) N:M 
A) 0:1 
B) 1:1 
C) 1:N 
D) N:1 
E) N:M

Question 17

When transforming a data model into a relational design,relationships of all degrees are treated as combinations of binary relationships.

Accepted Answer

A) True 
 B)False

Question 18

A binary relationship is a relationship between two or more entities.

Accepted Answer

A) True 
 B)False

Question 19

Which of the following is not a key element of an E-R model?

Accepted Answer

A) Identifiers 
B) Entities 
C) Objects 
D) Attributes 
E) Relationships 
A) Identifiers 
B) Entities 
C) Objects 
D) Attributes 
E) Relationships

Question 20

Describe and discuss the main elements of the Entity-Relationship (E-R)model.

Accepted Answer

The E-R model is basically made up of en

Exam 5: Data Modeling With the Entity-Relationship Model

Explain the ambiguity in the broad definition of a weak entity.

Entities can be associated with one another in relationships.

Subtype entities contain only attributes unique to the subtypes.

To represent an archetype/instance pattern in an E-R model,________.

The supremetype entity contains the attributes that are common to all subtypes.

Common variants of the E-R model include:

Distinguish between entity identifiers and keys.

An entity is something that users want to track.

Recursive relationships only exist for one-to-one relationships.

Relationships among instances of a single entity class are called redundant relationships.

-You are given an E-R diagram with two entities,ORDER and CUSTOMER,as shown above.What does the symbol next to the ORDER entity indicate?

An identifier may be ________.

An entity whose identifier includes the identifier of another entity is a(n)________.

Which of the following is considered to be a weak entity?

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

When transforming a data model into a relational design,relationships of all degrees are treated as combinations of binary relationships.

A binary relationship is a relationship between two or more entities.

Which of the following is not a key element of an E-R model?

Describe and discuss the main elements of the Entity-Relationship (E-R)model.

Introduction

Introduction to Structured Query Language SQL

The Relational Model and Normalization

Database Design Using Normalization

Transforming Data Models Into Database Designs

SQL for Database Construction and Application Processing

Database Redesign

Managing Multiuser Databases

Managing Databases With SQL Server 2008 R2

Managing Databases With Oracle Database 11g

Managing Databases With MySQL 55

The Web Server Environment

Database Processing With XML

Database Processing for Business Intelligence Systems

Microsoft Access 2010

Getting Started With Systems Analysis and Design

E-R Diagrams and the Idef1x Standard

E-R Diagrams and the UML Standard

Getting Started With MySQL Workbench Data Modeling Tools

Getting Started With Microsoft Visio 2010

the Semantic Object Model

Data Structures for Database Processing

Getting Started With Web Servers php and the Eclipse PDT

Filters