My first Publication Agile-Data-Warehouse-Design-eBook | Page 87

66
Chapter 3
If the stakeholders answer NO, you add CUSTOMER TYPE to the dimension as in
Figure 3-4. Try this question on something which doesn’t belong to CUSTOMER,
like the detail about detail PRODUCT TYPE:
Can a customer have more than one product type
at any one moment in time?
! long answer might be:
The short answer is YES; the stakeholder’s
Yes, a customer can buy or use several products with
different product types at any moment.
Product type obviously doesn’t belong to ! Customer and the YES answer confirmed
it. In reality, common sense would have prevented you or the stakeholders from
considering this as a CUSTOMER attribute.
Figure 3-4
Adding
CUSTOMER TYPE
to CUSTOMER
Sometimes you will also have to exercise a little intuition to interpret a YES (multi-
ple values are possible at any moment) answer. If you ask:
Can a customer have more than one customer address?
The answer could be YES but you intuitively
feel that CUSTOMER ADDRESS
!
belongs to CUSTOMER. How you solve this problem depends on just how many
interesting addresses a Customer has. You could ask:
Is there a single primary (easily identifiable) address for each
customer that should be used for geographic analysis?
If the answer is:
!
Yes, billing address.