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

Combining Correlated Dimensions

We stated previously that if a many-to-many relationship exists between two groups of dimension attributes, they should be modeled as separate dimensions with separate foreign keys in the fact table. Sometimes, however, you encounter situations where these dimensions can be combined into a single dimension rather than treating them as two separate dimensions with two separate foreign keys in the fact table.

Class of Service

The Figure 12-2 draft schema includes the class of service flown dimension. Following a design checkpoint with the business community, you learn the users also want to analyze the booking class purchased. In addition, the business users want to easily filter and report on activity based on whether an upgrade or downgrade occurred. Your initial reaction might be to include a second role-playing dimension and foreign key in the fact table to support both the purchased and flown class of service. In addition, you would need a third foreign...