Databases Reference
In-Depth Information
When database software and hardware are fine-tuned and bundled together,
they are called a
data warehouse appliance
. These concepts are included here
because they are commonly used and most readers have likely heard several
of these terms.
Diagramming Your Dimensional Model
There are different ways to document and present dimensional models. One of
the most common ways that dimensional models are depicted are as tables to
be stored in a relational database. The dimensional model can be documented
using the same modeling tool that is used to develop any other data models
for the relational database. Each of the dimensional attributes is included and
represented using logical names that should be meaningful to the business.
This type of table diagram is easily understood by systems professionals, but
it is not as clear to business professionals.
Another method to document your dimensional model is to present business
diagrams. The intent is to visually present the model in terms that more closely
reflect the interface that will ultimately be presented for access. This is called
business dimensional modeling
, and it can be documented using any visual
diagramming tool.
Careful analysis must be performed and dimensional modeling principles
must be followed in either case. The primary difference is how the model is
presented to the business. The diagram notation of the business dimensional
model is reviewed next. The process to develop a dimensional model is
discussed later in this chapter.
The Business Dimensional Model
With the increasing variety of options for building the data warehouse, it
is important to split the business perspective from the technical perspective
regarding the data. The
Business Dimensional Model (BDM)
isadatamodelthat
is specifically geared toward working with the business community. It serves
as an abstraction layer that insulates the model from technical implementation
details. The model also serves as a communication vehicle between the business
and systems groups. The model shows diagrams of the dimensions and the
facts so that the details can be reviewed and discussed in business terms. This
also separates the business discussion from any technical discussions.
The business side of the problem can be addressed in enough detail so that
the systems team can implement the model in any technology. Limited tech-
nical tips are shared at the end of this chapter to guide the project team when
implementing the dimensional model in a relational database management
