.: External Design
The goal of external design is to create a description of all elements of the application which interact with users or external systems.
The documentation and UI prototype which constitute this deliverable make it possible for stakeholders to manually “execute” usage scenarios and to confirm for themselves that the design, to this point, is compatible with their requirements and expectations.
The deliverables for external design normally consist of the following:
- User-interface. Documentation for the entire user interface. This includes menus, all screens and dialogs (or web pages), and any significant warning or error message windows. If the UI is at all complex, a UI navigational diagram is also provided which shows all possible routes through the user-interface and the conditions under which they would be taken.
A UI prototype is also created, which allows users to explore the user-interface, seeing exactly how it will look in the finished application. At this point the prototype consists solely of UI; no functionality or database access is enabled.
- Reports. In business systems, the key importance of reporting is often undervalued. Perhaps we should say: “If this system could endow you with perfect, effortless insight into a specific area of your business, what would you see? What would you know?”
That should be the starting point for report design. Yes, of course there are reports in any system that are utilitarian or mandated by legacy procedures. But all reporting, utilitarian or not, should aim to present exactly the needed information, in the simplest, clearest way possible, and should allow the user maximum flexibility in controlling how the information is selected, sorted and organized for physical presentation.
In other words, all your reports should look great, should be exceptionally informative and easy to understand, and you should be able to easily obtain from the system almost any information ever needed.
- Data imports / exports. Data imports and exports usually exist for one of two reasons. One, to communicate with other systems, either in-house or controlled by business partners. The other, to create data files you can easily manipulate with office tools such as word processors and spreadsheets.
The external specifications should identify each import and export, indicate its purpose, list the information to be exported or imported, and describe user options for selection and sorting.
- Web services interactions. If the system will interact with other systems via web services, the external design documents should describe the nature of the interaction, including its purpose, functional requests, and information exchange.
Discovery / Requirements
Problem Domain
Risks
Architecture
External Design
Functional Design
Implementation
Quality Assurance
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