My first Publication Agile-Data-Warehouse-Design-eBook | Page 185

6
W HO AND W HAT
Dimensional Design Patterns for People and Organizations, Products and Services
Who’s on first?
— Bud Abbott and Lou Costello
What’s next?
— President Jed Bartlet, “The West Wing”
Who and what dimensions such as CUSTOMER, EMPLOYEE and PRODUCT
represent some of the most interesting, highly scrutinized, and complex dimen-
sions of a data warehouse. Modeling these dimensions and their inherent hierar-
chies presents a number of challenges that can be addressed by design patterns. Who and what are
In the first of our W-themed design pattern chapters we begin by describing mini-
dimensions and snowflaking for handling large, volatile customer dimensions,
swappable dimensions for mixed customer type models and hierarchy maps for
recursive customer relationships. We then move on to employee dimensions to
cover hybrid SCD views for current value/historic value (CV/HV) reporting re-
quirements and multi-valued hierarchy maps for multi-parent HR hierarchies with
dotted-line relationships. We finish by looking at product and service dimension
issues and introduce multi-level dimensions for variable detail facts and reverse
hierarchy maps for component analysis. This chapter
Large, rapidly changing customer populations
the most important
dimensions
describes design
patterns for defining
flexible, high
performance who
and what
dimensions
Chapter 6 Design
Mixed business models: businesses and consumers, products and services Challenges
Simultaneous current and historic value reporting requirements At a Glance
Variable-depth hierarchies, recursive relationships
Multi-valued hierarchies
Business processes with variable levels of dimensional detail
Product bill of materials
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