10th slide set of CECS 542 How to engineer a domain model using UML or more informal notations

1. Requirements
Engineering:
Domain Models
CECS 542
Dr. Birgit Penzenstadler 1
Photo credit: John Towner, Unsplash

2. Context Layer
System Layer
Requirements Layer
Stakeholder Model Objectives
& Goals
Constraints
& Rules
!
!
!
!
!
Data Model
E
A
A
A
E
System Vision
Functional
Hierarchy
Architecture Overview
System
Function Model
Fun 1
Fun 2
Component Model
C C
Data Model
E
A
A
A
E
Behaviour Model
Business Case
Deployment Requirements
System Constraints
Domain Model
Service ModelUsage Model
Quality Requirements
Risk List
Project Scope
Process Requirements
Glossary
Glossary
Glossary
Today‘s learning goals
• What is a domain model?
– Defini?on, characteris?cs
– Rela?ons to other RE content
• Overview of
– Types of domain models
– Method for development
• Domain model in AMDiRE
• What are typical problems?
2

3. Defini?on
A domain model in problem solving and
soJware engineering is a conceptual model of
all the topics related to a specific problem.
It describes the various en??es, their
aMributes, roles, and rela?onships, plus the
constraints that govern the problem domain.
Dr. Birgit Penzenstadler 3

4. Ra?onale:
Why a domain model?
• Conceptual framework of
things in problem space
• Helps you think – and focus on seman?cs
• Provides a glossary of terms
• Sta?c view – structure of ?me-invariant parts
• Based on that structure, we can describe the
state of the problem domain at any ?me
(in behavioral, dynamic views)
Dr. Birgit Penzenstadler 4

5. Example: Simple domain model
Dr. Birgit Penzenstadler 5
Domain objects are not soJware objects, but a
representa?on of real-life conceptual objects.

6. Features
• Domain classes – each domain class denotes a type of object
– Business objects: things manipulated in the business, e.g., Order
– Real world objects: things the business keeps track of, e.g., Contact,
Site
– Events that transpire, e.g. Sale and Payment
• A<ributes – an aMribute is the descrip?on of a named slot of a
specified type in a domain class; each instance of the class
separately holds a value, e.g. name or ID
• Associa>ons – an associa?on is a rela?onship between two (or
more) domain classes that describes links between their object
instances, e.g., owns. Associa?ons can have roles, describing the
mul?plicity and par?cipa?on of a class in the rela?onship, e.g.
employee.
• Addi>onal rules – complex rules that cannot be shown with
symbology can be shown with aMached notes.
Dr. Birgit Penzenstadler 6

7. Rela?on to other
RE content
• Input
– Business Case
– Goal Model
• Output
– Glossary
– System Vision
(usually developed in
itera?on with Dom. Model)
– Usage Model
Dr. Birgit Penzenstadler 7
Context Layer
System Layer
Requirements Layer
Stakeholder Model Objectives
& Goals
Constraints
& Rules
!
!
!
!
!
Data Model
E
A
A
A
E
System Vision
Functional
Hierarchy
Architecture Overview
System
Function Model
Fun 1
Fun 2
Component Model
C C
Data Model
E
A
A
A
E
Behaviour Model
Business Case
Deployment Requirements
System Constraints
Domain Model
Service ModelUsage Model
Quality Requirements
Risk List
Project Scope
Process Requirements
Glossary
Glossary
Glossary

8. Domain Models
• Defini?on & characteris?cs
• Rela?on to other RE content
• Types of domain models and examples
• Method for development
• AMDiRE domain model
• What are the challenges?
Dr. Birgit Penzenstadler 8
K Rayker, stock.xchng

9. Example: Sample domain model for a
health insurance plan
Dr. Birgit Penzenstadler 9
[Kishorekumar, Wikimedia Commons 2009]

10. Example: Sample domain model for a
health insurance plan
Dr. Birgit Penzenstadler 10
[hMp://scaledagileframework.com/domain-modeling/]

11. Example: Sample domain model for a
health insurance plan
Dr. Birgit Penzenstadler 11
[hMp://scaledagileframework.com/domain-modeling/]

12. How to develop a DM
• Make a list of candidate domain classes – iden?fy nouns.
• Draw these classes in a UML class diagram.
• If possible, add brief descrip>ons for the classes.
• Iden?fy any associa>ons that are necessary.
• Decide if some domain classes are really just a<ributes.
• Where helpful, iden?fy role names and mul>plicity for
associa?ons.
• Add any addi?onal sta>c rules as UML notes that cannot
be conveyed with UML symbols.
• Group diagrams/domain classes by category into
packages.
Dr. Birgit Penzenstadler 12

13. Example: TENCompetence
learning
network
Dr. Birgit Penzenstadler 13
[hMp://dspace.ou.nl/handle/1820/649]

14. Example: Research Compu?ng
Domain Model
Dr. Birgit Penzenstadler 14
[hMp://www.bridging-the-gap.com/domain-models/]

15. Sources & QA
• Elabora?on from
– Business case analysis
– Stakeholder input (goals, constraints)
– Background research
• Quality: Completeness
– All important concepts of problem domain
– Adequate aMributes
– All important associa?ons
Dr. Birgit Penzenstadler 15

16. Domain Models
• Defini?on & characteris?cs
• Rela?on to other RE content
• Types of domain models and examples
• Method for development
• AMDiRE domain model
• What are the challenges?
Dr. Birgit Penzenstadler 16
K Rayker, stock.xchng

17. Elabora?on in
AMDiRE
• Hand sketch (draJ)
• Class diagram (itera?on)
Dr. Birgit Penzenstadler 17
Context Layer
System Layer
Requirements Layer
Stakeholder Model Objectives
& Goals
Constraints
& Rules
!
!
!
!
!
Data Model
E
A
A
A
E
System Vision
Functional
Hierarchy
Architecture Overview
System
Function Model
Fun 1
Fun 2
Component Model
C C
Data Model
E
A
A
A
E
Behaviour Model
Business Case
Deployment Requirements
System Constraints
Domain Model
Service ModelUsage Model
Quality Requirements
Risk List
Project Scope
Process Requirements
Glossary
Glossary
Glossary

18. Challenges
• Problem domain
(conceptual objects)
• Completeness
(classes, associa?ons, aMributes)
à The beMer your domain model,
the easier it will be to develop the
system vision and usage model.
Dr. Birgit Penzenstadler 18
Context Layer
System Layer
Requirements Layer
Stakeholder Model Objectives
& Goals
Constraints
& Rules
!
!
!
!
!
Data Model
E
A
A
A
E
System Vision
Functional
Hierarchy
Architecture Overview
System
Function Model
Fun 1
Fun 2
Component Model
C C
Data Model
E
A
A
A
E
Behaviour Model
Business Case
Deployment Requirements
System Constraints
Domain Model
Service ModelUsage Model
Quality Requirements
Risk List
Project Scope
Process Requirements
Glossary
Glossary
Glossary