What are four major elements of design model in software engineering ?

There are two dimensions in which a design model can be illustrated: process and abstraction dimension. Process dimension points the changes in the design model as the design tasks are implemented as part of software process. Abstraction dimension represents the level of detail as each element of analysis model is transformed into design equivalent and refined iteratively.

Design model elements are not developed in a sequential fashion. The design model has four major elements:
- Data
- Architecture
- Components
- Interface

Data design focuses on files or databases at an architectural level and on a component level, data design considers the data structures that are required to implement local data objects.

The architectural model is derived from the application domain, the analysis model and available styles and patterns.

The interface design elements for software tells us how the information flows in and out of the system and how it is communicated among the components. There are three parts to interface design elements: the user interface, interfaces to systems external to application and interfaces to components within the application.
User interface elements include aesthetic elements, ergonomic elements and technical elements. External interface design requires information about entity to which information is sent or received. Internal interface design is closely related to component level design.

The component level design elements describes the internal detail of software component. The component level design defines data structures for all local data objects and algorithmic detail processing that occurs within a component and an interface that allows access to all behaviors.