TRENDS IN DATABASE TECHNOLOGY - Database Design and Development: An Essential Guide for IT Professionals - page 642

OPERATIONAL
SYSTEMS

Key measurements,
business dimensions

Extraction,
cleansing,
aggregation

Basic
business
processes

Data
Transformation

DATA
WAREHOUSE

Executives/Managers/
Analysts

BLEND OF TECHNOLOGIES

Data
Acquisition

Applications

Analysis

Data Modeling

Data Quality Administration

Storage
Management

Data Manage-
ment

Metadata
Management

Development
Tools

Figure 20-12 Data warehouse: a blend of technologies.

the data, and the function of providing user interfaces. Different technologies are
therefore needed to support these functions. Figure 20-12 illustrates how various
technologies blend together in the data warehouse environment.
Although many technologies are in use, they all work together in a data ware-
house. The end result is the creation of a new computing environment for the
purpose of providing strategic information every enterprise needs desperately.
Several vendor tools are available in each of these technologies. You do not have
to build your data warehouse from scratch.

Nature of the Data It is important to consider the nature of the data in the data
warehouse. How are these data different from the data in any operational system?
Why does they have to be different? How is the data content in the data warehouse
used?

Subject-Oriented In operational systems, we store data by individual applica-
tions. For a banking institution, data sets for a consumer loans application contain
data for that particular application. Data sets for other distinct applications of
checking accounts and savings accounts relate to those specific applications.
Again, in an insurance company, different data sets support individual applica-
tions such as automobile insurance, life insurance, and workers' compensation
insurance.
In striking contrast, in the data warehouse, data are stored by subjects, not by
applications. What are business subjects? Business subjects differ from organization
to organization. These are the subjects critical for the enterprise. For a manufac-
turing company, sales, shipments, and inventory are critical business subjects. For a
retail store, sales at the check-out counter is a critical subject.
In a data warehouse, there is no application flavor. The data in a data warehouse
cut across applications.