Information Technology Reference
In-Depth Information
1-800-flowers.com uses a data
warehouse to reference customer
historical data. DBMS software
accessed over the corporate
intranet gives marketing
professionals the information they
need to determine customer
interests based on past
interactions.
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The primary advantage of data warehousing is the ability to relate data in innovative
ways. However, a data warehouse can be extremely difficult to establish, with the typical cost
exceeding $2 million. Table 5.7 compares online transaction processing (OLTP) and data
warehousing.
Data Marts
A
data mart
is a subset of a data warehouse. Data marts bring the data warehouse concept—
online analysis of sales, inventory, and other vital business data that has been gathered from
transaction processing systems—to small and medium-sized businesses and to departments
within larger companies. Rather than store all enterprise data in one monolithic database,
data marts contain a subset of the data for a single aspect of a company's business—for
example, finance, inventory, or personnel. In fact, a specific area in the data mart might
contain more detailed data than the data warehouse would provide.
Data marts are most useful for smaller groups who want to access detailed data. A ware-
house contains summary data that can be used by an entire company. Because data marts
typically contain tens of gigabytes of data, as opposed to the hundreds of gigabytes in data
warehouses, they can be deployed on less powerful hardware with smaller secondary storage
devices, delivering significant savings to an organization. Although any database software can
be used to set up a data mart, some vendors deliver specialized software designed and priced
specifically for data marts. Already, companies such as Sybase, Software AG, Microsoft, and
others have announced products and services that make it easier and cheaper to deploy these
scaled-down data warehouses. The selling point: Data marts put targeted business informa-
tion into the hands of more decision makers. For example, the Defense Acquisition University
(DAU), which is responsible for continuing education and career management for employees
of the U.S. Department of Defense, uses data marts to provide administrators, instructors,
mation from more than 50 disconnected sources, and the DBMS then organizes the
information into area-specific data marts, which produce reports accessible through an online
dashboard application. The system is estimated to save DAU personnel three to five years of
labor.
data mart
A subset of a data warehouse.
