Chapter 12 - Modelling Requirements

Question 1

What are Use Case diagrams?

Answer 1

Represent what the business or IT system need to provide

Question 2

How are Actors represented in Use Case diagrams?

Answer 2

Matchstick figures or rectangles

Question 3

How are Use Case represented in a diagram?

Answer 3

Oval with ‘Verb Noun’ naming convention

Question 4

How is the system boundary represented in a Use Case diagram?

Answer 4

Large box drawn around all Use Cases

Question 5

How are Associations represented on a Use Case diagram?

Answer 5

Lines drawn between Actors and Use Cases

Question 6

How are other systems represented on a Use Case diagram?

Answer 6

Rectangle with <> before name of the system

Question 7

How can a Use Case that is shared by multiple processes be represented?

Answer 7

<> on dotted line with arrowhead pointing towards the included Use Case

Question 8

How is a Use Case that is not mandatory for the current iteration shown on a Use Case diagram?

Answer 8

<> with dotted line arrowhead pointing back to original Use Case

Question 9

What is data modelling concerned with?

Answer 9

Data items (attributes) that system needs to keep

Grouping attributes (into entities)

Relationship between entities

Question 10

What is an entity?

Answer 10

Something the company wishes to collect and store data about

Question 11

Give examples of physical entities

Answer 11

Order

Customer

Supplier

Question 12

Give examples of Conceptual entities?

Answer 12

a Booking

an Appointment

Question 13

Give examples of Active entities

Answer 13

Meeting

Course

Question 14

How are entities represented on a diagram?

Answer 14

Box with a noun, always singular

Question 15

What is the difference between entity type and entity occurrence?

Answer 15

If entity type is Book, entity occurrence is a specific instance of a Book, such as Death on the Nile

Question 16

What are attributes?

Answer 16

Attributes describe entities

Eg Book may have attributes for Title, Author, Publisher, Price

Question 17

How are attributes represented on a diagram?

Answer 17

They aren’t.

They are usually defined in supporting documentation

Question 18

What is a Relationship?

Answer 18

Relevant business connection between two entities

Question 19

How are relationships represented on a data model?

Answer 19

Line linking associated entities

Question 20

What types of relation are there in a data model?

Answer 20

One to many 1:m

One to one 1:1

Many to many m:m

Question 21

How are one to many relationships represented on a data model?

Answer 21

Crow’s foot and solid line

Question 22

Give an example of one to many relationship between two entities

Answer 22

Order and Customer

A particular order will only be placed by one customer, but a customer may place many orders

Question 23

How are one to one entity relationships represented on a data model?

Answer 23

Solid line

Question 24

Give an example of a one to one relationship

Answer 24

Country and Capital

A country has one Capital and a city is Capital of just one country.

Question 25

What is optionality in data models?

Answer 25

The optionality of the relationship describes whether or not the entities at both ends must always coexist of whether one can exist without the other.

Question 26

How are fully mandatory relationships shown on a data model?

Answer 26

Solid lines

Question 27

How are fully optional relationships shown on a data model?

Answer 27

Dotted lines

Question 28

How are mandatory parent entities with optional child entities shown on a data model?

Answer 28

Dotted line from parent to solid crow’s foot attached to child

Eg Customer may not have placed any orders, but an order must always be placed by a customer

Question 29

How are optional parent entity with mandatory child entity shown in a data model?

Answer 29

Solid line from parent to dotted line crow’s foot attached to child

Eg An order does not need to be related to a Complaint, but any Complaints must concern at least one order

Question 30

How are many to many relationships resolved?

Answer 30

By adding a link entity to split them into two one to many relationships

Question 31

What are the problems with many to many relationships?

Answer 31

Mask omitted entities

Data Base Management Systems do not often support them

Question 32

How is the nature of the relationship between two entities clarified?

Answer 32

A relationship link phrase is constructed from the perspective of each entity

Question 33

What is an exclusive relationship in a data model?

Answer 33

Participation of an entity occurrence precludes it from participating in another.

Question 34

How is exclusivity represented in a data model?

Answer 34

Exclusivity arc

Example:

An Employee must be allocated to one Sales region or one Office

Question 35

What are alternative notation methods for data models?

Answer 35

Horizontal lines to indicate ‘one’

Circles to indicate optionality

Question 36

What are Objects?

Answer 36

An object is something we wish to hold data about

Eg Order Number VF1234

Question 37

What are Classes?

Answer 37

Classes provide the generic definition of the data items / attributes and objects.

Order VF1234 is an object of the class Order.

The class Order Account has attributes such as orderNumber and totalValue

Question 38

How are Classes represented in UML?

Answer 38

Rectangular boxes with three sections:

Name of the class (noun)

Attributes (lower case)

Operations

Question 39

What are Associations in class modelling?

Answer 39

Connections between classes

Question 40

What is Multuplicity?

Answer 40

Shows the business rules for association between classes through the minimum and maximum values in the association

Question 41

How are Generalised attributes shown?

Answer 41

Upward facing arrow indicating sub-classes inherit the attributes of the generalised class.