The Data Warehouse Toolkit: The Definitive Guide to Dimensional Modeling, 3rd Edition

Chapter 3

Retail Sales

The best way to understand the principles of dimensional modeling is to work through a series of tangible examples. By visualizing real cases, you hold the particular design challenges and solutions in your mind more effectively than if they are presented abstractly. This book uses case studies from a range of businesses to help move past the idiosyncrasies of your own environment and reinforce dimensional modeling best practices.

To learn dimensional modeling, please read all the chapters in this book, even if you don't manage a retail store or work for a telecommunications company. The chapters are not intended to be full-scale solutions for a given industry or business function. Each chapter covers a set of dimensional modeling patterns that comes up in nearly every kind of business. Universities, insurance companies, banks, and airlines alike surely need the techniques developed in this retail chapter. Besides, thinking about someone else's business is refreshing. It is too easy to let historical complexities derail you when dealing with data from your company. By stepping outside your organization and then returning with a well-understood design principle (or two), it is easier to remember the spirit of the design principles as you descend into the intricate details of your business.

Chapter 3 discusses the following concepts:

• Four-step process for designing dimensional models
• Fact table granularity
• Transaction fact tables
• Additive, non-additive, and ...