DESIGN CONCEPTS AND PRINCIPLES

What is it? Design is a meaningful engineering representation of something that is to be built. It can be traced to a customer’s requirements and at the same time assessed for quality against a set of predefined criteria for “good” design. In the software engineering context, design focuses on four major areas of concern: data, architecture, interfaces, and components. At the data and architectural level, design focuses on patterns as they apply to the application to be built. At the interface level, human often prescription our design approach. At the component level, a “programming approach” leads us to effective data and procedural designs.


Why is it important? You wouldn’t attempt to build a house without a blueprint, would you? You’d risk confusion, errors, a floor plan that didn’t make sense, windows and doors in the wrong place

What are the steps? Design begins with the requirements model. We work to transform this model into four levels of design details

What is the work product? Ultimately, a Design Specification is produced. The specification is composed of the design models that describe data, architecture, interfaces, and components. Each is a work product of the design process.

Each of the elements of the analysis model provides information that is necessary to create the four design models required for a complete specification of design. The flow of information during software design is illustrated in Figure 13.1.

The data design transforms the information domain model created during analysis into the data structures that will be required to implement the software. The data objects and relationships defined in the entity relationship diagram and the detailed data content depicted in the data dictionary provide the basis for the data design activity.