Step-by-step explanation:
There is no single set of design models that are required for a complete specification of a software design, as the specific models needed will depend on the particular software development methodology and the needs of the project. However, some common design models that may be used in a software design specification include:
Use case diagrams: Use case diagrams are used to model the interactions between the system and the external entities, including the actors and their actions.
Class diagrams: Class diagrams show the relationships between classes, objects, and interfaces in the system, and how they collaborate to achieve the system's functionality.
Sequence diagrams: Sequence diagrams show the interactions between objects in the system, and the order in which they occur, which can be used to specify the dynamic behavior of the system.
State machine diagrams: State machine diagrams show the transitions between different states of an object or system, which can be used to specify how the system behaves in different situations.
Activity diagrams: Activity diagrams show the flow of activities or processes in the system, and can be used to specify the steps that need to be taken to accomplish a particular task or goal.
Other design models that may be used in a software design specification include component diagrams, deployment diagrams, and communication diagrams, among others. The specific models needed for a particular project will depend on the requirements of the project, the development methodology used, and the preferences of the development team.