This document discusses associations, attributes, and domain modeling using class diagrams. It defines associations as relationships between instances of types that indicate a meaningful connection. It provides guidelines for identifying useful associations and describes how to notate associations and determine their multiplicity in class diagrams. The document also defines attributes as logical data values of an object and discusses how to model attribute quantities and units. Finally, it includes an example of modeling an association and its multiplicity.

1. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Module 2 - Static Use Case Modeling 1
Title of Topic:
Associations, Attributes
Course Code: 20CS501
Course Title: Object Oriented Analysis and Design
Session Number: 2.6
Faculty Name: Ms. P. Anantha Prabha
Academic Year: 2022 - 2023 (Odd Sem)

2. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Module 2 - Static Use Case Modeling 2
Module 2 - Static Use Case Modeling
2.1 Use Case Modeling: Modeling Requirements, Components
2.2 Use Case Identification and Description
2.3 Use Case Relationships
Use Case Modeling, Relating Use cases - Include-Extend-
Generalization
Class Diagram-Elaboration, Domain Model
2.5 Finding Conceptual Classes and Description Classes
2.6 Associations, Attributes, Domain Modeling Using Class Diagrams
2.7 Domain Model Refinement, Finding conceptual class Hierarchies-
Aggregation and Composition
CO3 Interpret Use Case relationships in Use Case Modeling
CO4 Identify the object and class relationships for building UML diagrams

3. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
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Associations
An association is a relationship between instances of
types that indicates some meaningful and interesting
connection

4. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes

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Useful Associations
• Associations for which knowledge of the relationship
needs to be preserved for some duration.
• Associations derived from the Common Associations
List.

6. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
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UML Association Notation
• An association is represented as a line between
classes with an association name.
• Associations are inherently bidirectional.
• Optional reading direction arrow is only an aid to the reader
of the diagram.

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Finding Associations
Common Association List
The common categories that are worth considering
are:
• A is a physical part of B . Eg: Wing-Airplane
• A is a logical part of B. Eg: SalesLineItem- Sale.
• A is physically contained in B . Eg: Register- Store.

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Common Associations List 2
• A is logically contained in B.
Eg:ItemDescription-Catalog.
• A is a description of B.Eg:ItemDescription- Item.
• A is a line item of a transaction or report
B.Eg:SalesLineItem-Sale.
• A is a member of B .Eg: Cashier-Store.
• A uses or manages B.Eg:Cashier-Register.

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Common Associations List 3
• A is known/logged/recorded/reported/captured in B.Eg:
Sale-Register.
• A is an organizational subunit of B .
Eg:Department-Store.
• A communicates with B. Eg:Customer- Cashier.
• A is next to B. Eg:City-City.

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Common Associations List 4
• A is related to a transaction B. Eg:
Customer-Payment.
• A is a transaction related to another
transaction B. Eg:Payment-Sale.
• A is next to B. Eg:City-City.
• A is owned by B. Eg:Register-Store.
• A is an event related to B. Eg:Sale-Customer.

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High-Priority Associations
• A is a physical or logical part of B.
• A is physically or logically contained in/on B.
• A is recorded in B.

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Associations Guidelines
• The knowledge of the relationship needs to be preserved
for some duration.
• Identifying conceptual classes is more important than
identifying associations.
• Avoid showing redundant or derivable associations.

13. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes
Multiplicity defines how many instances of a class A can be associated
with one instance of a class B

14. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes

15. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes
Naming Associations
Name an association based on a TypeName-VerbPhrase-TypeName format
where the verb phrase creates a sequence that is readable and meaningful in
the model context.

16. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes
 An association indicates that the system you are developing stores links
of some kind between the instances of the associated types.
 An association is a diagrammatic method of showing an attribute or pair
of attributes.

17. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes
 An attribute is a logical data value of an object.
 For example, a receipt (which reports the information of a sale)
normally includes a date and time, and management wants to know the
dates and times of sales for a variety of reasons. Consequently, the Sale
conceptual class needs a date and time attribute.

18. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Modeling Attribute Quantities and Units

19. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes

20. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes

21. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Association and Multiplicity
Association and Multiplicity-

22. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes

23. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Associations and Attributes

24. Session 6 – Associations, Attributes, Domain Modeling Using Class Diagrams
Try Yourself