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.

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