Datasheet

22
Part I: The Data Warehouse: Home for Your Data Assets
this story is usually mistaken as, “Put as much data as possible in the ware-
house.” In reality, the data warehouse just described was probably one that
focused exclusively on sales activity. Remember that although disposable
diapers and beer are dramatically different products, they’re both members
of the same type of data (retail products).
The following example emphasizes why you should be selective about what
goes in your data warehouse and not just assume that you have to get every
possible type of data from all the sources, just in case you want to ask your
data warehouse any question.
Suppose that you’re creating a data warehouse for a cruise ship company. As
shown in Figure 1-3, the Tucson Desert Cruise Ship Company (its motto is
“Who needs an ocean?”) uses four applications that handle different tasks:
✓ Reservations and cancellations
✓ Food-and-beverage service for all cruises
✓ All trip itineraries and after-the-fact information about the weather,
unusual events, and all onboard entertainment scheduling
✓ All crew assignments
Figure 1-3:
A fictional
company’s
proposed
data ware-
housing
environ-
ment.
Shared Data
Reservations
and
cancellations
Ship and crew
assignments
Tucson Desert Cruise
Ship Company
Data warehouse
Trip itinerary
and events
Food and
beverage
services
ADMIT
ONE
ADMIT
ONE
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