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

Slowly Changing Dimension Basics

To this point, we have pretended dimensions are independent of time. Unfortunately, this is not the case in the real world. Although dimension table attributes are relatively static, they aren’t fixed forever; attribute values change, albeit rather slowly, over time. Dimensional designers must proactively work with the business’s data governance representatives to determine the appropriate change-handling strategy. You shouldn’t simply jump to the conclusion that the business doesn’t care about dimension changes just because they weren’t mentioned during the requirements gathering. Although IT may assume accurate change tracking is unnecessary, business users may assume the DW/BI system will allow them to see the impact of every attribute value change. It is obviously better to get on the same page sooner rather than later.