Mastering Data Modeling: A User-Driven Approach [Paperback]

John Carlis (Author), Joseph Maguire (Author)

Book Description

Publication Date: November 19, 2000 | ISBN-10: 020170045X | ISBN-13: 978-0201700459

This book introduces Logical Data Structures (LDS), a powerful new approach to database design that can dramatically improve the cost-effectiveness and business value of any enterprise database system or database-driven application. The authors introduce a new notation, new diagramming approach, and new user-centered, high-ROI techniques for modeling even the most complex, high-volume database applications. This book starts from first principles, asking and answering crucial questions like: "To best serve users, how should the process of data modeling work? To create good, economical software systems, what kind of information should be on a data model? To become an effective data modeler, what skills should you master before talking with users?" Next, it teaches data modeling using LDS, designed to encourage a user-centered, requirements approach that leads directly to more effective applications. The authors walk you through the entire process of creating and enhancing a data model. For all database administrators, analysts, designers, and architects, and for all IT managers responsible for enterprise database system management or deployment.

Editorial Reviews

From the Inside Flap

This book teaches you the first step of creating software systems: learning about the information needs of a community of stran

This book teaches you the first step of creating software systems: learning about the information needs of a community of strangers. This book is necessary because that step--known as data modeling--is prone to failure.

This book presumes nothing; it starts from first principles and gradually introduces, justifies, and teaches a rigorous process and notation for collecting and expressing the information needs of a business or organization.

This book is for anyone involved in the creation of information-management software. It is particularly useful to the designers of databases and applications driven by database management systems.

In many regards, this book is different from other books about data modeling. First, because it starts from first principles, it encourages you to question what you might already know about data modeling and data-modeling notations. To best serve users, how should the process of data modeling work? To create good, economical software systems, what kind of information should be on a data model? To become an effective data modeler, what skills should you master before talking with users?

Second, this book teaches you the process of data modeling. It doesn’t just tell you what you should know; it tells you what to do. You learn fundamental skills, you integrate them into a process, you practice the process, and you become an expert at it. This means that you can become a "content-neutral modeler," moving gracefully among seemingly unrelated projects for seemingly unrelated clients. Because the process of modeling applies equally to all projects, your expertise becomes universally applicable. Being a master data modeler is like being a master statistician who can contribute to a wide array of unrelated endeavors: population studies, political polling, epidemiology, or baseball.

Third, this book does not focus on technology. Instead, it maintains its focus on the process of discovering and articulating the users’ information needs, without concern for how those needs can or should be satisfied by any of the myriad technological options available. We do not completely ignore technology; we frequently mention it to remind you that during data modeling, you should ignore it. Users don’t care about technology; they care about their information. The notation we use, Logical Data Structures (LDS), encourages you to focus on users’ needs. We think a data modeler should conceal technological details from users. But historically, many data modelers are database designers whose everyday working vocabulary is steeped in technology. When technologists talk with users, things can get awkward. In the worst case, users quit the conversation, or they get swept up in the technological details and neglect to paint a complete picture of their technology-independent information needs. Data modeling is not equivalent to database design.

Another undesirable trend: historically, many organizations wrongly think that data modeling can be done only by long-time, richly experienced members of the organization who have reached the status of "unofficial archivist." This is not true. Modeling is a set of skills like computer programming. It can be done by anyone equipped with the skills. In fact, a skilled modeler who is initially unfamiliar with the organization but has access to users will produce a better model than a highly knowledgeable archivist who is unskilled at modeling.

This book has great ambitions for you. To realize them, you cannot read it casually. Remember, we’re trying to foster skills in you rather than merely deliver knowledge to you. If you master these skills, you can eventually apply them instinctively.

Study this book the way you would a calculus book or a cookbook. Practice the skills on real-life problems. Work in teams with your classmates or colleagues. Write notes to yourself in the margins. An ambitious book like this, well, we didn’t just make it up. For starters, we are indebted to Michael Senko, a pioneer in database systems on whose work ours is based. Beyond him, many people deserve thanks. Most important are the many users we have worked with over the years, studying data: Gordon Decker; George Bluhm and others at the U. S. Soil Conservation Service; Peter O’Kelly and others at Lotus Development Corporation; John Hanna, Tim Dawson, and other employees and consultants at US WEST, Inc.; Jim Brown, Frank Carr, and others at Pacific Northwest National Laboratory; and Jane Goodall, Anne Pusey, Jen Williams, and the entire staff at the University of Minnesota’s Center for Primate Studies. Not far behind are our students and colleagues. Among them are several deserving special thanks: Jim Albers, Dave Balaban, Leone Barnett, Doug Barry, Bruce Berra, Diane Beyer, Kelsey Bruso, Jake Chen, Paul Chapman, Jan Drake, Bob Elde, Apostolos Georgopolous, Carol Hartley, Jim Held, Chris Honda, David Jefferson, Verlyn Johnson, Roger King, Joe Konstan, Darryn Kozak, Scott Krieger, Heidi Kvinge, James A. Larson, Sal March, Brad Miller, Jerry Morton, Jose Pardo, Paul Pazandak, Doug Perrin, John Riedl, Maureen Riedl, George Romano, Sue Romano, Karen Ryan, Alex Safonov, Wallie Schmidt, Stephanie Sevcik, Libby Shoop, Tyler Sperry, Pat Starr, Fritz Van Evert, Paul Wagner, Bill Wasserman, George Wilcox, Frank Williams, Mike Young, and several thousand students who used early versions of our work. Thanks also go to Lilly Bridwell-Bowles of the Center for Interdisciplinary Studies of Writing at the University of Minnesota. Several people formally reviewed late drafts of this book and made helpful suggestions:Declan Brady, Paul Irvine Matthew C. Keranen, David Livingstone, and David McGoveran. And finally, thanks to the helpful and pat ent people at Addison-Wesley. Paul Becker, Mariann Kourafas, Mary T. O ’Brien, Ross Venables, Stacie Parillo, Jacquelyn Doucette, the copyeditor, Penny Hull, and the indexer, Ted Laux. How to Use This Book

To study this book rather than merely read it, you need to understand a bit about what kind of information it contains. The information falls into eight categories.

Introduction and justification. Chapters 1 and 2 define the data-modeling problem, introduce the LDS technique and notation, and describe good habits that any data modeler should exhibit. Chapters 22 and 24 justify in more technical detail some of the decisions we made when designing the LDS technique and notation.
Definitions. Chapter 4 defines the vocabulary you need to read everything that follows. Chapter 13 defines things more formally--articulating exactly what constitutes a syntactically correct LDS. Chapter 23 presents a formal definition of our Logical Data Structures in a format we especially like--as an LDS.
Reading an LDS. Chapter 3 describes how to translate an LDS into declarative sentences. The sentences are typically spoken to users to help them understand an in-progress LDS. Chapter 5 describes how to visualize and annotate sample data for an LDS.
Writing an LDS. Chapter 13 describes the syntax rules for writing an LDS. Chapter 14 describes the guidelines for naming the parts of an LDS. Chapter 15 describes some seldom-used names that are part of any LDS. Chapter 16 describes how to label parts of an LDS. (Labels and names differ.) Chapter 17 describes how to document an LDS.
LDS shapes and recipes. Chapter 7 introduces the concept of shapes and tells how your expertise with them can make you a master data modeler. Chapters 8 through 12 give an encyclopedic, exhaustive analysis of the shapes you will encounter as a data modeler. Chapter 26 describes some recipes--specific applications of the shapes to common problems encountered by software developers and database designers.
Process of LDS development. Chapters 6 and 21 give elaborate examples of the process of LDS development. Chapter 18 describes a step-by-step script, called The Flow, that you follow in your conversations with users. Chapters 19 and 20 describe steps you can take to improve an in-progress LDS at any time--steps that do not fit into the script in any particular place because they fit in every place. Considered as a whole, Chapters 18 through 20 describe the process of controlled evolution, the process by which you guide the users through a conversation that gradually improves the in-progress LDS. "Controlled" implies that the conversation is organized and methodical. "Evolution" implies that the conversation yields a continuously, gradually improving data model.
Implementation and technology issues. Chapter 22 describes in detail the forces that compel us to exclude constraints from the LDS notation. Many of these forces stem from implementation issues. Chapter 25 describes a technique for creating a relational schema from an LDS.
Critical assessment of the LDS technique and notation. Chapter 24 describes the decisions we made in designing the LDS technique and notation and

From the Back Cover

Data modeling is one of the most critical phases in the database application development process, but also the phase most likely to fail. A master data modeler must come into any organization, understand its data requirements, and skillfully model the data for applications that most effectively serve organizational needs.

Mastering Data Modeling is a complete guide to becoming a successful data modeler. Featuring a requirements-driven approach, this book clearly explains fundamental concepts, introduces a user-oriented data modeling notation, and describes a rigorous, step-by-step process for collecting, modeling, and documenting the kinds of data that users need.

Assuming no prior knowledge, Mastering Data Modeling sets forth several fundamental problems of data modeling, such as reconciling the software developer's demand for rigor with the users' equally valid need to speak their own (sometimes vague) natural language. In addition, it describes the good habits that help you respond to these fundamental problems. With these good habits in mind, the book describes the Logical Data Structure (LDS) notation and the process of controlled evolution by which you can create low-cost, user-approved data models that resist premature obsolescence. Also included is an encyclopedic analysis of all data shapes that you will encounter. Most notably, the book describes The Flow, a loosely scripted process by which you and the users gradually but continuously improve an LDS until it faithfully represents the information needs. Essential implementation and technology issues are also covered.

You will learn about such vital topics as:

• The fundamental problems of data modeling
• The good habits that help a data modeler be effective and economical
• LDS notation, which encourages these good habits
• How to read an LDS aloud--in declarative English sentences
• How to write a well-formed (syntactically correct) LDS
• How to get users to name the parts of an LDS with words from their own business vocabulary
• How to visualize data for an LDS
• A catalog of LDS shapes that recur throughout all data models
• The Flow--the template for your conversations with users
• How to document an LDS for users, data modelers, and technologists
• How to map an LDS to a relational schema
• How LDS differs from other notations and why

"Story interludes" appear throughout the book, illustrating real-world successes of the LDS notation and controlled evolution process. Numerous exercises help you master critical skills. In addition, two detailed, annotated sample conversations with users show you the process of controlled evolution in action.

020170045XB04062001

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Product Details

• Paperback: 416 pages
• Publisher: Addison-Wesley Professional (November 19, 2000)
• Language: English
• ISBN-10: 020170045X
• ISBN-13: 978-0201700459
• Product Dimensions: 9.3 x 7.3 x 0.8 inches
• Shipping Weight: 1.5 pounds (View shipping rates and policies)
• Average Customer Review: 4.2 out of 5 stars  See all reviews (9 customer reviews)
• Amazon Best Sellers Rank: #910,882 in Books (See Top 100 in Books)

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Most Helpful Customer Reviews

45 of 51 people found the following review helpful:

3.0 out of 5 stars Beware- there's alot more to Data Modeling than this!, November 20, 2001

By 

Shelby Nichols (Los Angeles, CA) - See all my reviews

This review is from: Mastering Data Modeling: A User-Driven Approach (Paperback)

I disagree that a person could become a "master" data modeler if the contents of this book are the complete set of skills in their arsenal. While the book outlines some good techniques for interviewing end users and basic data modeling skills, there is alot more involved in data modeling than what is covered here.

As an experienced data modeler who works with large, complex data models in a constantly changing business, I find I do not refer to this book at all. The book excludes common data modeling constructs that I have found very useful, including subtypes and supertypes. The book does not explain the difference between conceptual, logical, and physical data modeling. (It covers techniques used to capture conceptual/logical level data, but nowhere does it explain that or the difference between this type of model and a physical model, and why and when you'd need one or the other.)

The book does not cover normalization, which, once one leaves the interview with end users, one will need to understand. The book does not mention data integration with other systems or databases, how this topic is important and could (and often should) arise in interviews with end users.

Some of the topics covered I found shallow and incomplete, for example, how to name things in a data model. The authors take a parochial view by ignoring real world issues such as using consistent names across database and organizations, and avoiding naming things for what they are used for, not what they are.

As a practicing data modeler, I find my users aren't as naieve about data models as Carlis and Maguire assume them to be. I often am asked why I am modeling data in a given way. In my view, this book does not address the "why" - why do you model the data in the way suggested, and what happens if you don't. When I can answer these questions well for my customers, I earn approval, and this book doesn't equip one to do so.

In sum, my belief is that this book contains about 1/4 of the information a person needs to know to become a "master" data modeler. It's a good starter book if you are a novice data modeler or are having trouble gathering information from business subject matter experts, but if you really want to become an expert data modeler, I'd recommend continuing beyong this book. I prefer 'Data Modeling Essentials 2nd Edition' by Graeme Simsion

14 of 15 people found the following review helpful:

5.0 out of 5 stars Excellent book, very efficient method, April 11, 2001

By 

Laurent Chassot ([e-mail]) - See all my reviews

This review is from: Mastering Data Modeling: A User-Driven Approach (Paperback)

The book describes a method to structure any given sets of data according to generic rules. Eventhough my background does not allow me to judge the theoretical validity of the method, the book is easy to read and all the concepts are easy to understand and described in details. I have applied the Carlis and Maguire method for modeling data in a small research group and it is brilliant. The method allows users to discuss their data in their own language and the modeler can build a logical representation which is understood and well accepted by the users. I will certainly use this book and the method for any future database design.

14 of 16 people found the following review helpful:

5.0 out of 5 stars Very important book., September 11, 2002

By A Customer

This review is from: Mastering Data Modeling: A User-Driven Approach (Paperback)

The secret is out!

I've been using the techniques described in this book for years because one of the authors taught me. I've used them to model data about research science, business, and topology. Now others can learn it too.

Carlis cured me of normalization. There's a difference between normalization and "normal forms". A goal of modeling is to produce databases in high normal forms - Boyce-Codd Normal Form, fifth normal form, etc... Most modelers think the only way to do this is through normalization, a specific process that step-by-step improves to a draft model. This book shows how to avoid that process completely. I used to do normalization. Now I use the conversational techniques of this book to reach high normal forms sooner. One thing I always hated about Normalization was that I usually did it after talking to users, which means I was making decisions that the users should have been making. I have not performed normalization in at least ten years. Yet I still produce databases in high normal form. This book does include a chapter about normalization, with normal forms up to fifth, so you can see for yourself how the technique produces high-normal-form databases. If you learned that normalization was essential part of data modeling, this chapter will help you learn this different way of working. If you are new to data modeling, you should start with this book to avoid learning normalization altogether. The principles of high normal forms are important, but the process of normalization is ludicrous.

This is a book about data modeling, not physical database design. It concentrates on the modeling in users' language. The naming conventions it recommends are based on guidelines of language and categories. If you follow these naming guidelines, you will not need to learn a huge list of more specific, special-case naming rules.

I also like what Carlis and MaGuire say about constraints. By following their constraint advice, I have become a much faster data modeler, and my team mates (programmers, DBAs) do not have to wait so long for me to finish my work. It also helps me keep my data models flexible, good for a changing business environment.

This book has more examples than any book on modeling I have ever seen. I stopped counting sample data models when I got to 300.

The hardest part of application design is understanding the user's data. This book concentrates on solving that problem, leaving the technical details of database design to other books.