The Data Warehouse Lifecycle Toolkit

CHAPTER 1

Introducing the

Kimball Lifecycle

B

efore delving into the specifics of data warehouse/business intelligence

(DW/BI) design, development, and deployment, we want to first introduce

the Kimball Lifecycle methodology. The Kimball Lifecycle provides the overall

framework that ties together the various activities of a DW/BI implementation.

The Lifecycle also ties together the content of this book, setting the stage and

providing context for the detailed information that unfolds in the subsequent

chapters.

This chapter begins with a historical perspective on the origination and

evolution of the Kimball Lifecycle. We introduce the Lifecycle roadmap,

describing the major tasks and general guidelines for effectively using the

Lifecycle throughout your project. Finally, we review the core vocabulary used

in the book.

We recommend that all readers take the time to peruse this brief introductory

chapter, even if you are involved in only one facet of the DW/BI project. We

believe it is beneficial for the entire team to understand and visualize the

big picture and overall game plan. This chapter focuses on the forest; each

remaining chapter will turn its attention to the individual trees.

Lifecycle History Lesson

The Kimball Lifecycle methodology first took root at Metaphor Computer

Systems in the 1980s. Metaphor was a pioneering decision support vendor;

its hardware/software product offering was based on LAN technology with a

relational database server and graphical user interface client built on a 32-bit

operating system. Nearly a quarter century ago, analysts in large corporations

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2 Chapter 1 ■ Introducing the Kimball Lifecycle

were using Metaphor to build queries and download results into spreadsheets

and graphs. Sounds familiar, doesn’t it?

Most of this book’s authors worked together to implement decision support

solutions during the early days at Metaphor. At the time, there were no

industry best practices or formal methodologies. But the sequential steps of

decision support were as obvious then as they are now; our 1984 training

manual described them as extract, query, analysis,andpresentation.

The authors and other Metaphor colleagues began honing techniques and

approaches to deal with the idiosyncrasies of decision support. We had

been groomed in traditional development methodologies, but we modified

and enhanced those practices to address the unique challenges of providing

data access and analytics to business users, while considering growth and

extensibility for the long haul.

Over the years, the authors have been involved with literally hundreds

of DW/BI projects in a variety of capacities, including vendor, consultant,

IT project team member, and business user. Many of these projects have been

wildly successful, some have merely met expectations, and a few have

failed in spectacular ways. Each project taught us a lesson. In addition,

we have all had the opportunity to learn from many talented individuals

and organizations over the years. Our approaches and techniques have been

refined over time — and distilled into The Data Warehouse Lifecycle Toolkit.

When we first published this book in 1998, we struggled with the appropriate

name for our methodology. Someone suggested calling it the Kimball Lifecycle,

but Ralph modestly resisted because he felt that many others, in addition to

him, contributed to the overall approach.

We eventually determined that the official name would be the Business

Dimensional Lifecycle because this moniker reinforced the unique core tenets

of our methods. We felt very strongly that successful data warehousing

depends on three fundamental concepts:

Focus on the business.

Dimensionally structure the data that’s delivered to the business via ad

hoc queries or reports.

Iteratively develop the overall data warehouse environment in manage-

able lifecycle increments rather than attempting a galactic Big Bang.

Rewinding back to the 1990s, we were one of the few organizations empha-

sizing these core principles at the time, so the Business Dimensional Lifecycle

name also differentiated our methods from others in the marketplace. Fast

forwarding to today, we still firmly believe in these core concepts; however

the industry has evolved since the first edition of the Lifecycle Toolkit was

published. Now nearly everyone else touts these same principles; they’ve

become mainstream best practices. Vocabulary from our approach including