Database Reference
In-Depth Information
You also need to compare the interview and observation notes against
the use of the existing application. Are there manual processes that support
the application? In other words, do users have to take extra steps to
make the application function or to add or change data already stored in
the application? Certain user actions—such as formatting phone numbers
in a field that contains a series of numbers with no format—indicate prob-
lems in the existing system that could be fixed in the database itself.
Use Cases
If you're familiar with common software engineering theory, you know the
concept of use cases.
Use cases
describe various scenarios that convey
how users (or other systems) will interact with the system that is being de-
signed to achieve specific goals or business functions. Generally, use cases
avoid highly technical language in favor of natural language explanations of
the various parts of the system in each scenario. This allows business ana-
lysts, management, and other nontechnical stakeholders to understand
what the system is doing and how it helps the business succeed.
From a design standpoint, the process of building use cases provides
deeper insight into what is required of the system. Use cases are logical
models in that they are concerned only with tasks that need to be com-
pleted and the order in which they must be done, without describing how
they are implemented in the system. To build effective use cases, it is es-
sential to work with various end users who will be interacting with the sys-
tem once it is built. They will help provide, via the techniques we've talked
about so far, low-level detail on the actual work that needs to be accom-
plished, without being distracted by technical implementation details.
To effectively present a new design, you often need to develop at least
two kinds of use cases: one for the existing process, and one for the new
process. This practice helps nontechnical stakeholders understand the dif-
ferences and reassures them that the value from the current system will be
carried forward to the new system.
A number of references are available that can give you detailed infor-
mation on developing use cases; for our purposes, we present a template
that covers most aspects of use case description, along with a simple use
case diagram. Feel free to use these in your project work.
Now let's take a look at building a sample use case.
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