Sunday, October 16, 2016


When I discussed with a book publisher the idea of a guide/reference to misconceptions about data fundamentals, whose objective -- distinct from the usual cookbooks -- is to help data professionals base their practice on understanding, rather than cookbooks, he said "they are not interested in understanding, only in succeeding in their jobs". Apparently, the former is no longer a factor in the latter. Given the increasingly deteriorating experiences I had with publishers, it was time to stop bothering with them -- they pay and do very little -- and self-publish.

THE DBDEBUNK GUIDE TO MISCONCEPTIONS ABOUT DATA FUNDAMENTALS  - A DESK REFERENCE FOR THE THINKING DATA PROFESSIONAL AND USER is now available for purchase ($35, order via the BOOKS page (not to be confused with the RECOMMENDED BOOKS page); contact me by email for volume discounts). 

From the Preface:

"Over the years I debunked myths and misconceptions in articles, papers, books, lectures, seminars and my consulting practice. The IT industry is riddled with them, but the most common and persistent ones have not been cataloged and explained systematically in a desk reference, accessible to the busy IT professional, that can be consulted regularly. This is the gap this book fills.

  • While common distortions, misuses and abuses of data and relational fundamentals remain entrenched, in the years since the old site, aside from new developments in the database field, our understanding of the Relational Data Model (RDM) as introduced by Codd and refined/extended by Date, Darwen, McGoveran and others has improved considerably.
  • Much of the site material was in the form of informal Q&A exchanges between my readers and me—a format that I wanted to preserve—but not always sufficiently focused, clear, precise, thorough and succinct for a desktop reference.
  • My perspective on some aspects has changed and my explanatory skills have improved.
  • Importantly, This is a good opportunity to incorporate some of David McGoveran’s interpretation of the Relational Data Model (RDM), one that he believes Codd intended, but continues to be misunderstood.
Why not revise the exchanges to reflect how I would debunk the misconceptions today, based on the current state of knowledge?

The guide consists of 50 sections, each based on a carefully selected exchange from the first generation of the DATABASE DEBUNKINGS website. Each documents and debunks one or more common and entrenched myths/misconceptions/fallacies about data and relational fundamentals that have costly implications. Instead of a Table of Contents, there is an Index of Misconceptions that references, for each, all the sections in which it is discussed possibly in different contexts, or with different emphasis.

The number of sections referenced is an indicator of how common each misconception is.

  • Data independence (logical, integrity, physical)
  • Data integrity (business rules, integrity constraints, database consistency)
  • Data models (relational, hierarchic, network)
  • Relational data sublanguage (vs. computationally complete language)
  • Database and application-specific functions
  • Domains (simple, non-simple, derived) vs. data types
  • Entity supertype-subtypes (and inapplicable data)
  • Keys (natural, primary, surrogate)
  • Levels of representation (conceptual, logical, physical)
  • Missing data (NULL, many-valued logics)
  • Normalization, further normalization, denormalization, normal forms
  • Relational Data Model
  • Relations (base, derived) and R-tables
  • SQL and relational fidelity
  • Types of model (conceptual, logical, physical, data)
  • "Unstructured data" (documents, NoSQL)"
From the Foreword by David McGoveran:

"Database practitioners, faced with a lack of commercial DBMS products that are truly relational, often need ready answers to undeserved criticisms and help understanding the sources of frustrations. They need the support, guidance, and encouragement of authorities like Fabian, as they champion the fight for better practices and better products. This book is unusual—in fact, unique—in several ways:

  • First, it is a collection of actual examples of questions raised by readers of DBDebunk, and Fabian’s response which seek to address relational fundamentals rather than merely providing superficial answers to those questions. The questions are used to catalog a broad sweep of misunderstandings regarding the relational data model and related issues. Misconceptions about relational fundamentals have pervaded the data management industry before DBDebunk and, sadly, are compounded today. Many of the included questions also illustrate the fuzzy thinking and poor communication so common in the industry. Longtime fans of DBDebunk will no doubt recognize some of the material. Trying to find all this material would be next to impossible, let alone in the readable form presented here.
  • Second and very important, Fabian’s responses have been updated and I am certain even longtime readers of DBDebunk will benefit from Fabian’s updated responses. Over the past few years, Fabian has been the unfortunate recipient of very early drafts of my forthcoming and long promised book LOGIC FOR SERIOUS DATABASE FOLKS. We’ve engaged in numerous discussions regarding my own research and re-evaluations of Codd’s early publications with the result that—for better or worse—many of his updated responses take those discussions into account and are published here for the first time.
  • Third, the style of this book is neither a tutorial about, nor an exposition on the subject matter. It is a structured as a reference. That is not to say that you should not take the time to read it from beginning to end. You definitely should. Having done so, however, the book should be kept close at hand. When asked questions about or are confronted with criticisms about the relational data model, you will likely find a relevant response here: few if any questions or criticisms about the relational data model are new and the appropriate responses have not changed much since its inception in 1980. (Sadly, most of the problems with alleged  implementations of the relational data model have not changed since 1980 either!) On the other hand, important subtleties continue to surface as our understanding of the depth of Codd’s thinking improves. I encourage you to read, think, and read again.
It is my fond hope that Fabian will continue to add to this collection and to expound upon the answers already in it. After you read the book, I’m sure that you will agree with me."

Any questions, suggestions, corrections are welcome, preferrably via the Comments section of this page, or email.

If you are interested in reviewing it for publication on your blog, or on other social or review sites, or can refer it to reviewers/review sites, please contact me by email. If you come across a review, please notify me. Thanks.

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  1. data professionals are smarter than you think.

  2. Few may well be smart, but even fewer are wise and thinkers. And besides, if they are, that'll be good for my book. I'm not holding my breath.