REQUIREMENTS GATHERING - A Developer's Guide to Data Modeling for SQL Server - page 111

Unified Modeling Language
UML is a standards specification established and maintained by the Object
Management Group (OMG). UML establishes a common language that can be
used to build a blueprint for software systems. More information can be found at
the OMG Web site at www.omg.org.
This diagram lays out the individual relationships between each use
case in the conference call system. The use case we documented, “Make
Reservation,” is a base use case that includes the “Manage Bridge Lines”
use case, and it is extended by the functionality in the “Create Customer
Record” use case. Additionally, you can see that both the “Run Confer-
ence” and “Bill Customer” use cases inherit properties from the “Make
Reservation” use case. And finally, you can see the principals (or actors)
that trigger the use cases. This diagram, when combined with the use case
descriptions for each use case, can help everyone involved in the project
talk through the entire system with a common reference in place.
Remember that most projects have a great many of these diagrams. As
a data modeler, you're responsible for understanding most these diagrams,
because most of them either input data into the system or retrieve and up-
date data already in the system. Thus, it is important to attend the use case
modeling meetings and to make sure to include your input into how each
system interacts with the company's data.
Business Needs
In case it hasn't been said enough in this topic so far, now is a good time to
remind you: Applications, and their databases, exist only to meet the needs
of an enterprise, whether it's a business, a school, or a nonprofit venture.
This means that one of the most important aspects of application design,
and the design of the application's supporting database, is to develop a
strong understanding of the organization's needs and to figure out how
your design will meet those needs.
To identify the business needs, you usually meet with the key stake-
holders. Usually, the organization has already identified a business need (or
needs) before initiating a development project. It is your job, however, to
identify the specific needs that are being addressed by the application that