Business Rules Applied: Building Better Systems Using the Business Rules Approach

495 Pages·2001·0.66 MB·English

by  Barbara von Halle

Business Rules Applied—Business Better Systems
Using the Business Rules Approach
Barbara von Halle
Wiley Computer Publishing
John Wiley & Sons, Inc.
Publisher: Robert Ipsen
Editor: Robert Elliot
Developmental Editor: Emilie Herman
Managing Editor: John Atkins
Associate New Media Editor: Brian Snapp
Text Design & Composition: Publishers’ Design and Production Services, Inc.
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Copyright © 2002 by Barbara von Halle. All rights reserved.
Published by John Wiley & Sons, Inc., New York
Published simultaneously in Canada.
Chapter 13 and 14 includes text and screen shots copyrighted by the following vendors:
HNC Software (p. 476–489). ©2001 Brokat Technologies; ILOG, Inc. (489–491). ©2001
ILOG Inc.; Usoft, Inc. (433–450). ©2001 Ness Usoft Group; Versata, Inc. (p. 450–471)
©2001 Versata, Inc.
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Library of Congress Cataloging-in-Publication Data:
Von Halle, Barbara.
Business rules applied : building better systems using the business rules approach /
Barbara von Halle.
p. cm.
Includes index.
ISBN 0-471-41293-7 (pbk. : alk. paper)
1. Business. 2. Industrial management. 3. Business—Data processing. 4. Industrial
management—Data processing. I. Title.
HD31 .V594 2001
658—dc21 2001046536
10 9 8 7 6 5 4 3 2 1
Advance Praise for Business Rules Applied
“Today’s fast-paced, competitive business environment demands flexible applications
that can be adapted to meet changing business requirements. Insurance companies,
financial institutions and other policy intensive organizations must develop applications
that allow the easy modification and implementation of business and regulatory policy.
Telecommunications companies must design their customer relationship management
and billing systems to support frequent new product and service offerings. Application
service providers must be able to rapidly customize their software to meet the unique
business requirements of each individual customer. More and more companies are
looking to business rules for the answer.
Business rule technology delivers a key technical capability. However, like other
technologies that promise to simplify and speed application development—object-
oriented languages like Java and C#, platforms like J2EE and .NET, and data
representations like XML—business rule technology alone cannot ensure a successful
application. The promise of more flexible, adaptable applications, where business rules
are managed separate from the application, can only be realized by good application
design. Business rule technology vendors provide powerful enabling tools—but the
success of the application depends on a thorough understanding of business
requirements and an application design that implements those requirements.
Little information is available today addressing the design and development of business
rule applications. How should business rules be identified? How should they be
represented? At what phase should they be integrated into the system development life
cycle? How do business rules work with object-oriented applications and relational
databases? How are business rules implemented in applications? These are among the
issues addressed by Business Rules Applied. As Barbara von Halle’s bestselling
Handbook of Relational Database Design guided data analysts and data base
administrators, this book will help business analysts and developers build applications
using business rules. This is an important book for those looking to implement business
rule technology.”
Colleen McClintock
JRules Product Manager, ILOG, Inc.
“With her book Business Rules Applied, Barbara von Halle puts the information
systems design discipline at a higher level. Placing rules as a third design principle
between data modeling and workflow concepts, she bridges a gap that until now has
only been bridged by the object-oriented modeling techniques like UML. The book
takes the reader all the way from early business level requirements analysis to the
precise actual realization of the system. The author takes a step-by-step approach,
describing the rules analysis and design process in regular terms of the IT professional.
This book opens up a new world to anybody interested in capturing business logic in a
structured way and from a business perspective.
For every phase of development the book explains how to position the rules
perspective in relation to the ‘normal’ way of working when modeling data and process
only. Through crisp and clear guidelines and working from a detailed real-world case,
the methodology described is truly effectuated for the reader. With this book von Halle
opens up the business rules way of thinking to a wider audience. It offers a new and
practical perspective on information systems development, that every software
engineer and business systems analyst should add to his toolkit.”
Paul Mallens
Author of the USoft Approach to Business Rules Automation
Delft University of Technology, the Netherlands
“Business Rules Applied is an excellent reference for anyone developing business
systems that must respond to change. Starting with four core principles for business
rules development, Barbara von Halle takes us on a tour of the rule-enriched systems
development life cycle, illustrating the differences and advantages of a business rules
approach at each and every step. Written in a methodology- and technology-agnostic
manner, Business Rules Applied will prove compelling and educational to all
developers—including those with business rules technology, and those unlucky enough
to be without.”
Steven Sweeting
Director, Product Management, Versata, Inc.
“There are only a handful of classic books that define the data and information
management industry. Barbara von Halle has now written two of those books. Business
Rules Applied defines business rule development the same way that the Handbook of
Relational Database Design defined data modeling and database design back in 1988.
Business Rules Applied is a must-read for all professionals that are serious about
managing their business rules.”
Robert S. Seiner
Publisher, “The Data Administration Newsletter” (TDAN.com)
“The author has provided significant insight into how IT systems might be made more
agile and responsive to business needs. Business rule concepts are introduced and a
case made for their adoption. A rule-based method for development is then provided
which is built on simple but powerful principles, and which melds with existing object-
oriented development approaches. The flexible approach is supported by many
insightful guidelines together with a substantial case study. The case study adds
particular value because it is used throughout the life cycle to draw out key insights and
includes implementation in a number of commercial rule engines. Significant
consideration is given to how to architect, design, and manage for rules under different
business development constraints (e.g. financial, time to market), in order to provide
value in a changing business environment.”
Duncan McMillan
“I have been waiting for Barbara von Halle and her colleagues at KPI to encapsulate for
the rest of the world what their team has been putting into practice for the past half-
decade. This book represents a wonderful accomplishment, an integrated, time-tested,
means of using business rules to build better systems. Two primary accomplishments
of the text are worth pointing out: First, how much more effectively new systems can be
made using the intelligence that is currently tied up in organizational legacy code.
Second, how much better the new systems will be able to support organizational
objectives because of lower system maintenance and better architectural engineering.
My hat is off to Barbara and the rest of KPI—this book will quickly become a must read
in the business rules community and beyond as word of these successes spreads.”
Peter Aiken, PhD
Co-author of Building Corporate Portals with XML
To kindergarten tee-ball players everywhere.
Acknowledgments
Without a doubt, this book would not be possible were it not for the efforts and moral
support of many special people. For starters, I would like to express my gratitude to
early reviewers, Neela Waghmare, Nancy Shipley, and Chip Didden, who pored over
initial manuscripts, submitted questions, and worked on solutions to the case study. I
am indebted to Grace Van Etten who also reviewed chapters, especially regarding
technical points. A very special thank you goes to Janet Wall and Linda Nieporent who
devised the detailed case study and its solution, giving the book a fun but realistic
target business rules system. There is a special thank you to Linda Nieporent who
devised useful rule techniques and created various case study solution documentation.
Additional gratitude goes to Art Moore and Janet Wall for assisting in the coordination
of contributors and to Janet Wall for coordinating vendor correspondence.
I also want to offer a sincere expression of gratitude to Janet Wall, Art Moore, and
Neville Haggerty, all of whom wrote many versions of various chapters, mostly during
nonworking hours. They never seemed to get tired of working on this book.
All of us who worked on the book are grateful for the contributions and dedication of
business rules vendors in exploring and implementing our case study. Without their
contributions, the book would be deficient in alternatives in a full business rules
solution. We are especially grateful for their patience with our questions through email
and conference calls. From ILOG Inc., we want to thank Colleen McClintock and
Steven Paulin. From USoft Inc., we appreciate the incredibly quick and thorough
response from Sjors Niesten and Rob Haarst. From HNC Software, we owe our thanks
to Ken Mollay, Vince Emery, Eric Odell, and Tom Goering. From Versata Inc., we are
indebted to Steven Sweeting for working on the case study against difficult deadlines as
well as his support and encouragement throughout the book project. We would also like
to thank Tony Phillips, formerly of Versata Inc., who wrote a valuable Versata
methodology document.
The truth is that this book would never have been possible without the encouragement
and support of every employee of Knowledge Partners Inc. (KPI). Only because KPI
employees were willing to take on some of my regular job responsibilities was I able to
dedicate significant time to the book. Other employees graciously accepted that the
book writing would impact my ability to participate in all company activities. Therefore,
in one way or another, all KPI employees made a sacrifice for this book. I am, as
always, amazed at and humbled by their unending and sincere support.
I would like to extend a very special thank you to Bob Elliott of Wiley and Sons who
encouraged me throughout the years to eventually write a business rules book. Also
deserving recognition is Emilie Herman of Wiley and Sons, whose regular
encouragement, support, and advice assisted every step of the way.
No one can write a business rule book without giving tremendous credit to Ronald G.
Ross. His intellectual depth, publications, teaching, consulting, and persistence in the
field of business rules have created tremendous opportunity for business rule
practitioners and vendors.
Every book project has its unplanned challenges. Sadly, as this book neared its
completion, I was diagnosed unexpectedly with breast cancer. I am forever grateful to
Dr. Vivien Chou whose diligence and intuition would not let go of a cancer that seemed
to defy detection. As a result of the diagnosis, my life was changed forever and it was
sometimes difficult to keep up with book deadlines amid medical appointments. I am
therefore grateful to medical doctors, Dr. Robert Goodman, Dr. Jan Huston, and Dr.
Richard Michaelson, who were flexible with my schedule. In particular, the caring and
cheerful attitudes of John Tirado and Lauralee Curcione in the radiation department
kept my spirits in the right place, day after day after day. I am also grateful to everyone
within KPI, my family, and Wiley (especially Emilie Herman), whose support and caring
during this time allowed me to complete the project as originally scheduled.
As always, I am personally indebted to my husband of 24 years, Mike von Halle, for his
never-ending belief in and support for me. Without his dedication and assistance in both
our personal and business lives, this book would never have been possible.
About the Authors
Barbara von Halle is the founder of Knowledge Partners, Inc. (KPI). She plays many
roles in the company, from strategic planning to career development of employees. She
is best known for pioneering in the world of Data Architecture and Business Rules
through writings and consulting work. In 1996, she received the honored Outstanding
Individual Achievement Award from the International Data Management Association.
She was a leading contributing editor for Database Programming and Design
magazine, co-authored The Handbook of Relational Database Design, and co-edited
The Handbook of Data Management.
About the Contributors
Neville Haggerty is a Principal Consultant with Knowledge Partners, Inc. He has 34
years of experience in information management. For the past 17 years, he has held
information technology management consultant positions specializing in facilitating
communications between business and information technology people. Most recently,
Neville introduced clients to templates for capturing business requirements, extended
System Architect to include the capture of business rules, and facilitated rule scoping
sessions. Neville has been utilizing these skills and techniques in soliciting and storing
business rules for various business rule projects.
Art Moore is a Principal with Knowledge Partners, Inc. He has experience in consulting
practice management, methodology development, project management, and delivery
oversight in information architecture, data warehousing, and a business rules approach
to systems specification. He played a key role in developing and testing a business rule
mining methodology. Most recently, he has been applying formal facilitation skills to the
soliciting of business rules.
Linda (Jeney) Nieporent is a Principal Consultant with Knowledge Partners, Inc. She
has seven years of experience as a consultant, instructor, and speaker in data
architecture and business rules, including working for a CASE tool vendor. Assisting
clients in soliciting data requirements and business rules, she creates corresponding
data models and correlates them to rules. Most recently, she has been integrating
business rules analysis into data modeling activities and exploring how rules technology
vendors support the implementation of rule-oriented systems.
Janet Wall is a Principal with Knowledge Partners, Inc., and provides leadership in
business development, employee mentoring, and development of Intellectual Property.
Previously, Janet was Director of IRM and of Applications Development for a
pharmaceutical research institute. Janet has been a key member of member of a
business rule methodology team. She coordinates business rule experiences and
deliverables and assists in future methodology development.
Foreword
Business rule systems—evolutionary or revolutionary? The best answer is “yes.” I say
that without tongue in cheek.
The really big changes are always based on a matter of degrees. Small quantitative
differences can become large qualitative ones. A football game, as they say, can be
won by inches. Heat water to 99 degrees Centigrade, and you still have a liquid. Heat it
a bit more, though, and you get something quite different.
The Business Rule Approach has been in a long period of incubation, gradually heating
up degree-by-degree all through the 1990s. Refinements in the approach have come in
many small increments by dedicated pioneers in out-of-the-spotlight corners of the IT
world. But for those of us fortunate enough to have participated in this process, we
have always known the approach would eventually come into its own in a big way. As
I’ve said many times in my lectures and seminars, business rules are inevitable!
Why? Well, Barbara is about to tell you why. Just plunge into Part 1 and you’ll quickly
get the picture. No need for me to repeat that here.
Here’s where I want to focus: small quantitative differences producing big qualitative
ones. Heat the water just a bit more, and you get steam. Harness that steam on an
industrial scale, and you get a source of new power far beyond anything before. The
trick from a business point of view, of course, is all in the timing. The winners usually
wait until the approach is proven, but jump in before competitors.
As I write this today, that’s exactly where we are in the Business Rule Approach. As
Barbara’s book demonstrates, there is a whole new source of power to meet IT needs
in the 21st century—business rule methodology. Barbara lays this out in wholesome
detail in Parts 2 through 5 of her book.
I also agree with her when she points out that you don’t necessarily need a new engine
to benefit from that. But let me be straight about this. I believe there is a rule engine in
your future—and probably sooner than you think.
“If things would only slow down some,” you might say, “coding rules in procedural
languages would work just fine.” But therein lies the flaw. With each passing year, do-
ing business is inexorably moving faster, not slower. And there’s no sign of that letting
up. I believe your business will inevitably move toward knowledge automation—rule
engines—simply because it is already feeling so much heat. Quantitative differences
produce qualitative ones.
Back now to the original question: Business rule systems—evolutionary or
revolutionary? Like I said, the answer is yes. Let me quote Barbara on this. In the
Summary of Chapter 3 she writes, “At first glance, you may believe that this book does
not contain any new ideas. This is a natural first impression because you have always
dealt with all aspects of a system, regardless of what you called those aspects or which
is your favorite system development paradigm. However, this book proposes that the
Rule Track . . . makes all the difference in the world in the world to the business itself”
[emphasis mine]. There you have it—evolutionary yet revolutionary.
Just one more thing before I close. On a personal note, let me thank you, Barbara, for
all those regular Friday afternoon phone discussions on business rules back in the
early- and mid-1990s when I was writing (incubating, really) The Business Rule Book.
On a cabinet in my office I have a note from that period predicting that you would write
a book about business rule methodology for IT professionals by the year 2000. (Really
true—the ink is even faded.) Just one question: Why were you a year or two late? No
matter, it was worth waiting for!
Ronald G. Ross
Principal, Business Rule Solutions, LLC
Executive Editor, www.BRCommunity.com
Table of Contents
Business Rules Applied—Business Better Systems Using the

Business Rules Approach
Foreword
Preface
Part I - Business Rule Basics
Chapter 1 - The Need for a Business Rules Approach
Chapter 2 - Business Rule Concepts
Chapter 3 - Introduction to Business Rule Methodology
Part II - Getting Started on Business Rules Project
Chapter 4 - Scoping for Success
Chapter 5 - Project Planning with Business Rules
Part III - Discovery
Chapter 6 - Discovering Initial Requirements
Chapter 7 - Discovering Rules and Data
Chapter 8 - Discovering Rules through Facilitated Sessions
Part IV - Analysis
Chapter 9 - Analyzing Data
Chapter 10- Analyzing Rules
Chapter 11- Analyzing Process
Part V - Design
Chapter 12- Designing for a Business Rules Approach
Implementing Business Rule Systems Using Data-
Chapter 13-
Change-Oriented Rules Products
Implementing Business Rule Systems Using Service-
Chapter 14-
Oriented Products
Chapter 15- Rule Management
References
Index
Preface
A business rules approach to systems development promises to be the most practical
and desirable way to build systems. It can help you build better, easily changeable
systems faster than any previous approach. This book provides a step-by-step practical
approach for building systems using a business rules approach.
The timing of the emergence of a business rules approach is compelling. Adaptability is
a subtle but powerful change in the way we build systems. As a parallel, let’s look at
how the emergence of relational concepts and corresponding technology took place.
Ted Codd documented his relational model in a landmark paper in 1970. Subsequently,
small software vendors created database management systems based on a subset of
the concepts of the relational model. Shortly after that, major software vendors did the
same. Around that time, authors like C.J. Date published books and gave presentations
that explained the concepts of the new software to the IT industry. Eventually, people
such as Candy Fleming and I published books and gave courses in how a practitioner
can proceed from gathering requirements to using the new software for creating
relational databases.
Relational technology flourished for many reasons:
(cid:131) It was theoretically sound.
(cid:131) Software vendors understood the theory, to some extent, and delivered
commercial products.
(cid:131) IT notables, such as C.J. Date, eloquently explained the theory, benefits, and
practicality of relational products to the IT industry.
(cid:131) Other practitioners gained early experience and developed step-by-step
approaches for using the new software.
Let’s now evaluate the evolution of the business rules approach. Ted Codd laid the
groundwork for the integrity aspect of the relational model back in 1970. While this
aspect has not been fully deployed by relational DBMS vendors, it had made strides
through triggers and stored procedures and in research under the auspices of active
database systems.
Innovative software vendors (such as Versata Inc, Brokat Technologies, USoft Inc.,
ILOG Inc., The Haley Enterprise, and Rule Machines Inc.) incorporated those concepts
into a type of software product called commercial rules technology. These products are
used mostly by application developers, less so by database professionals, because the
product environments promote the idea that those integrity constraints, the business
rules, are part of the application development world.
In addition, Ronald G. Ross has published further theory on the classification and
grammar of the various types of integrity constraints, or business rules. C.J. Date
published a book for IT practitioners that explains the history of the business rule
phenomenon as it relates to the relational model, as well as the adoption process for
software vendors. He further acknowledges that, while specification of constraints
(business rules) can be part of a fully matured relational database management
system, there are benefits to doing so in a middle tier that manages the rules
independently of the DBMS.
So, as for the business rules approach:
(cid:131) It is theoretically sound.
(cid:131) Vendors understand the theory, to some extent, and are delivering commercial
products.
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(cid:131) C.J. Date and Ronald G. Ross have explained the theory and product
capabilities to the IT Industry.
It is now time for a step-by-step approach for applying the theory to technology in the
world of e-business, Web-based, object-oriented, and relational database systems
development. This book combines best practice systems design principles plus
adherence to the principles of a business rules approach, thereby enriching what you
already know how to do.
A system built according to the business rules approach has many advantages over
other systems. However, given the pressures of e-commerce, the most important
advantage is that a business rules system is designed to easily accommodate changes
in the business with minimal disruption. Therefore, this book introduces a new
emphasis and formalism around capturing, validating, and automating the rules of the
business so that the business can easily change those rules as it sees fit.
The methodology in this book builds on familiar methodologies such as structured
systems analysis, information engineering, and object-orientation so that readers can
easily add a business rules approach to existing practices. The most significant aspect
of this book is the introduction of a rule track into a systems development methodology.
The steps, guidelines, techniques, and examples of activities in this track guide the
reader in understanding what business rules are, why they are important to the
business, why it is important not to bury the business rules in code again, and how to
analyze and deliver the rules as a valuable, changeable aspect of the resulting system.
Defining the Business Rules Approach
A business rules approach is merely a formal way of managing and automating an
organization’s business rules so that the business behaves and evolves as its leaders
intend. Essentially, a business rules system is an automated system in which you
separate the rules, logically, perhaps physically, and share them across data stores,
user interfaces, and applications.
You can apply most of the concepts in this book regardless of whether you utilize
special rules technology, although use of such technology will deliver the most
immediate and long-lasting benefits. As a starting point, during scoping for example,
you will pay special attention to the business motivation for your project. Aspects of this
motivation may include objectives, goals, strategies, tactics, and policies. These are the
fundamental justification for the rules you uncover, deliver, and change during the
systems development effort.
During the discovery of requirements, you will seek important decisions behind the
target system and dissect these into atomic rules, capturing them in a rules repository.
You can extend an existing repository, utilize an existing CASE tool, or build a simple
rules database.
Moving into analysis, you become involved in steps and techniques specifically aimed
at verifying the quality of rules, connecting rules to information and knowledge, and
understanding dependencies among rules.
Finally, in the design phase, you consider implementation options, paying close
attention to those that allow you to deliver the rules in a way that accomplishes four
significant objectives:
(cid:131) Separate rules from the rest of the system so you can reuse them
(cid:131) Trace rules to the reasons they exist as well as to where they are implemented
(cid:131) Externalize rules so everyone can know what they are
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