OBJECT ORIENTED ANALYSIS & DESIGN

Structured Analysis and structured Design

1. 
   Reduce maintenance time and effort
2. 
   Makes it easier to go back to earlier phases in the life cycle when necessary.
3. Emphasis on portioning or dividing a problem into smaller, more manageable units and making a clear distinction between physical and logical design.

Object –oriented Analysis and design
 

1. OOAD is a third approach to system development, after the process –oriented and data-oriented approaches
2. Systems development methodologies and techniques based on objects rather than data or processes.
3. The goal of OOAD is to make system elements more reusable thus improving system quality and the productivity of systems analysis and design.
4. 
   The primary tasks of object oriented analysis are identifying objects, defining their structure and behavior and defining their relationship.
5. The primary tasks of OOD are modeling the details of the object's behavior and communication with other objects so that system requirements are met and reexamining and redefining objects to better take advantage of inheritance and other benefits of object-orientation.

-With traditional system development and structured techniques analysis and design are separate but
overlapping steps, and different techniques are used for analysis and for design.
- Object-oriented model is popular because of its ability to thoroughly represent complex relationship, as
well as to represent data and data processing with consistent notation.
- A model is an abstraction of the real world and it allows us to deal l with the complexity inherent in a realworld
problem by focusing on the essential and interesting features of an application.
- The principles of objects, encapsulation, inheritance and polymorphism are the foundation for objectoriented
system development.