Book Image

The Data Warehouse Toolkit - Third Edition

By : Ralph Kimball, Margy Ross
5 (1)
Book Image

The Data Warehouse Toolkit - Third Edition

5 (1)
By: Ralph Kimball, Margy Ross

Overview of this book

The volume of data continues to grow as warehouses are populated with increasingly atomic data and updated with greater frequency. Dimensional modeling has become the most widely accepted approach for presenting information in data warehouse and business intelligence (DW/BI) systems. The goal of this book is to provide a one-stop shop for dimensional modeling techniques. The book is authored by Ralph Kimball and Margy Ross, known worldwide as educators, consultants, and influential thought leaders in data warehousing and business intelligence. The book begins with a primer on data warehousing, business intelligence, and dimensional modeling, and you’ll explore more than 75-dimensional modeling techniques and patterns. Then you’ll understand dimension tables in-depth to get a good grip on retailing and moved towards the topics of inventory. Moving ahead, you’ll learn how to use this book for procurement, order management, accounting, customer relationship management, and many more business sectors. By the end of this book, you’ll be able to gather all the essential knowledge, practices, and patterns for designing dimensional models.
Table of Contents (31 chapters)
Free Chapter
1
Cover
2
Title Page
3
Copyright
4
About the Authors
5
Credits
6
Acknowledgements
29
Index
30
Advertisement
31
End User License Agreement

Dimension Attribute Hierarchies

Although the budget chain use case described in this chapter is reasonably simple, it contains a number of hierarchies, along with a number of choices for the designer. Remember a hierarchy is defined by a series of many-to-one relationships. You likely have at least four hierarchies: calendar levels, account levels, geographic levels, and organization levels.

Fixed Depth Positional Hierarchies

In the budget chain, the calendar levels are familiar fixed depth position hierarchies. As the name suggests, a fixed position hierarchy has a fixed set of levels, all with meaningful labels. Think of these levels as rollups. One calendar hierarchy may be day image fiscal period image year. Another could be day image month image year. These two hierarchies may be different if there is no simple relationship between fiscal periods and months. For example, some organizations have 5-4-4 fiscal periods, consisting of a 5-week span followed by two 4-week spans. A single calendar date dimension...