Object-Oriented Software Development-Three Models

Three models are usually required to develop software using object-oriented methods:
Object Model: describes the system data structure
Dynamic Model: describes the system control structure
Function Model: describes system functions.

What is an object model?
The object model represents the "data" nature of a static and structured system.
The object model maps objects in the simulated objective world and the relationships between objects. It describes the static structure of the system.

What is a dynamic model?
The dynamic model represents the "control" nature of the instantaneous and behavioral system and specifies the sequence of valid changes of objects in the object model. That is, the dynamic behavior of the object.
A state chart is used to describe the state of an object, events that trigger state conversion, and actions of an object (response to an event ).
The dynamic behavior of each class is illustrated by a state chart. The state diagrams of each class are combined by sharing events to form a dynamic model of the system.

What is a functional model?
The function model indicates the "function" nature of the changed system. It specifies what the system should "do", so it directly reflects the user's requirements for the target system.
Representation Method
A functional model is also typically represented by a set of data flowcharts.
In object-oriented methods, data flowcharts are not important in structural analysis, and can be omitted sometimes.