Class Modeling is a technique used in object-oriented analysis and design to represent the structure of a system by identifying its classes, attributes, methods, and relationships. It focuses on modeling the static aspects of a system, showing how objects are organized and how they interact with one another.

1. Unit 2: Class Modeling
Object and Class Concepts

2. Introduction to Class Modeling
• Class modeling describes the static structure
of a system
• Shows classes, objects, and their relationships
• Forms the foundation of Object-Oriented
Design

3. Objects
• Object is an instance of a class
• Represents a real-world entity
• Has:
– Identity
– State (attributes)
– Behavior (methods)

4. Classes
• Class is a blueprint for creating objects
• Defines:
– Attributes (data)
– Operations (functions)
• Multiple objects can be created from one class

5. Relationship Between Object and Class
• Class defines structure and behavior
• Object represents actual entity at runtime
• Example:
– Class: Student
– Object: Student1, Student2

6. Class Diagrams
• Graphical representation of classes
• Shows:
– Class name
– Attributes
– Methods
• Also displays relationships between classes

7. Values and Attributes
• Attribute:
– Property of a class
• Value:
– Data stored in an attribute
• Example:
– Attribute: marks
– Value: 85

8. Operations and Methods
• Operation:
– Declared function in a class
• Method:
– Implementation of operation
• Defines object behavior

9. Links and Associations
• Link:
– Connection between objects
• Association:
– Relationship between classes
• Shows how classes interact

10. Multiplicity
• Specifies number of objects in an association
• Common multiplicities:
– 1
– 0..1
– 1..*
– 0..*

11. Association Names and Ordering
• Association name:
– Describes meaning of relationship
• Ordering:
– Sequence of associated objects
• Improves clarity of model

12. Association Classes
• Used when association has its own attributes
• Combines class and association
• Example:
– Student — Course
– Association class: Enrollment

13. Qualified Association
• Uses a qualifier to reduce multiplicity
• Acts like a key
• Example:
– Bank → Account (accountNumber)

14. Generalization and Inheritance
• Represents IS-A relationship
• Child class inherits attributes and methods
• Example:
– Person → Student, Teacher

15. Use of Generalization & Sample Class Model
• Promotes:
– Reusability
– Extensibility
• Parent class contains common features
• Child classes contain specialized features

16. Thank You