1. INFS 6225 Object Oriented Systems Analysis & Design
Chapter 5: Structural Modeling

2. Structural Models Represents the data used & created by a system
Describes data captured & how data relate to each other
Are logical models
Are technology-independent (in Analysis Phase)
Typically used for “To Be” System

3. Relationships in Structural Modeling
Generalization – “is a kind of” ex. Employee is a kind of Person
Aggregation – “is a part of” ex. Door is a part of a Car
Association – “catch all” ex. Patient & Appointment are Associated

4. Anthropomorphism To treat classes as if they were human.
Who or what are you?
What do you know?
What can you do?
Helps to create CRC Cards

5. Structural Model: 2 Parts
CRC Card (Class Responsibility Collaboration)
Written form used to document responsibilities & collaborations of a class
Used to build Class Diagram
Class Diagram (similar to ER Diagram)
Graphical model of classes & relationships among classes
CRC Cards are created first; Class Diagrams are then created from CRC Cards

6. CRC Cards Front: Class name: ID: Type: Description:
Responsibilities : Collaborators:
Back:
Attributes:
Relationships:
Generalization (a-kind-of):
Aggregation (has-parts):
Other Associations:

7. Class Diagram

8. Class Diagram Components
A CLASS
AN ATTRIBUTE
AN OPERATION
AN ASSOCIATION
Class 1
-attribute
+operation ()
Attribute name/
derived attribute name
operation name ()
1..* 0..1
______verb phrase____

9. Notes on Attributes
Derived Attributes “/” calculated from other attributes ex. Age
Public Attributes “+” Not hidden from any other object
Protected Attributes “#” Hidden from other objects (except subclasses)
Private Attributes “-” Hidden from all other objects

10. Notes on Relationships
A Class can be related to itself
Relationships involve Multiplicity
Also called Cardinality
Zero to One
Zero to Many
One to One
One to Many
Many to Many, et al.

11. Practice Exercises