Object-oriented analysis and design (OOAD) is a technological approach to analyze, design a software system or business by using Object Oriented (OO) concept. Object Oriented Analysis (OOA) is the investigation of objects. Object Oriented Design (OOD) is the relationships of identified objects.
The most important purpose of OO analysis is to identify the objects of a system that have to be implemented. This analysis can also perform for an existing system. An efficient analysis is only possible when we think in a way where objects can be identified. After identifying the objects the relationships between them are identified and finally the design is produced.