This book is all about answering business questions. One subject area at a time, we will demonstrate how business needs can be represented in a data warehouse design, and how that design can be used to answer business questions.
While most computer systems are designed to capture data, data warehouses are designed for getting data out. This fundamental difference suggests that the data warehouse will be designed according to a different set of principles. Before we begin presenting solutions for various businesses, we must outline these principles.
The solutions we build follow a set of design principles called dimensional modeling, often referred to as the star schema approach. Although not new, the star schema has recently been popularized by Ralph Kimball. In his book, The Data Warehouse Toolkit (John Wiley and Sons, 1998), Dr. Kimball outlines the principles of dimensional modeling, using terminology that we will follow. We highly recommend Dr. Kimball's book to anyone involved in the design and implementation of a data warehouse.
If you haven't read The Data Warehouse Toolkit, this chapter is meant for you. It is a quick primer on dimensional modeling. Although not a replacement for Dr. Kimball's book, it provides the fundamentals that will be required to understand the designs in this book. You may want to skip this chapter if you are familiar with dimensional modeling; however, we suggest you review the summary of terms at the end of ...