Battle of the Giants - Comparing Kimball and Inmon

DW MODELS

Data Warehousing Battle of the Giants:

Comparing the Basics of the Kimball and Inmon Models

Mary Breslin

Many organizations today need to create data warehouses— massive data stores of time-series data used for decision support. These organizations face a range of choices, both in terms software tools and development approaches. Making good choices requires an understanding of the two main data warehousing models— Inmon’s and Kimball’s. Bill Inmon advocates a top-down development approach that adapts

Mary Breslin has worked in both user and IT roles and she is currently exploring Capella University’s data warehouse from the user side. marybreslin@earthlink.net

traditional relational database tools to the development needs of an enterprisewide data warehouse. From this enterprisewide data store, individual departmental databases are developed to serve most decision support needs. Ralph Kimball, on the other hand, suggests a bottom-up approach that uses dimensional modeling, a data modeling approach unique to data warehousing. Rather than building a single enterprisewide database, Kimball suggests creating one database (or data mart) per major business process. Enterprisewide cohesion is accomplished by using another Kimball innovation, a data bus standard. Understanding how these two models are similar and how they differ gives the reader a foundational knowledge of the most basic data warehouse concepts. We will also explore which organizational characteristics are best suited to each approach.

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BUSINESS INTELLIGENCE JOURNAL • WINTER 2004

DW MODELS

Introduction and Context

We begin our discussion by defining the data warehouse. We will introduce the Inmon-Kimball debate, and provide a brief history of the evolution of the two models. We also provide a brief explanation of the nature of the data warehouse, and conclude with a discussion of the scope of the article.

Context of the Inmon-Kimball Debate

A data warehouse contains...