Object Diagram(对象图)

Object diagrams are derived from class diagrams so object diagrams are dependent upon class diagrams.

Object diagrams represent an instance of a class diagram.
Object diagrams also represent the static view of a system but this static view is a snapshot of the system at a particular moment.

类图是系统组件抽象的层次 对象图是类图的具象化

Purpose of Object Diagrams

a class diagram represents an abstract model consisting of classes and their relationships.
an object diagram represents an instance at a particular moment, which is concrete in nature.

a object diagram is closer to the actual system behavior.

Understood object behavior and their relationship from practical perspective!

Draw an Object Diagram

an object diagram is an instance of a class diagram.
In Class Diagrams elements are in abstract form to represent the blue print
In Object Diagrams elements are in concrete from to represent the real world object

• analyze the system and decide which instances have importance data and association
• consider only those instances, which will cover the functionality
• make some optimization as the number of instances are unlimited

Think twice!!!

• Object diagrams consists of objects.

If a different time of purchase is considered, then these values will change accordingly.

Where to User Object Diagrams?

In a nutshell, it can be said that object diagrams are used for -
🔸Making the prototype of a system.
🔸Reverse engineering.
🔸Modeling complex data structures.
🔸Understanding the system from practical perspective.

优秀博文：

1. https://baike.baidu.com/item/对象图/4670794?fr=aladdin
2. https://www.jianshu.com/p/2899f93a484a