date on database

CYAN MAGENTA YELLOW BLACK PANTONE 123 CV this print for content only—size & color not accurate 7" x 9-1/4" / CASEBOUND / MALLOY (1.125 INCH BULK 568 pages 50# Thor) THE EXPERT’S VOICE ® IN DATABASE C. J. Date Date on Database Writings 2000–2006 BOOKS FOR PROFESSIONALS BY PROFESSIONALS ® Date on Database: Writings 2000–2006 Dear Reader, This book brings together all of my shorter database writings from the period 2000–2006 that I think worth preserving. Some discuss comparatively new topics—for example: • Sixth normal form • Type inheritance and substitutability • Multiple assignment • The Principle of Orthogonal Design • Relations and trees • Business rules and the relational model • Temporal data (how not to do it) Others have new things to say about older topics, including: • Data redundancy and • The true nature of first normal form database design • Problems of left-to-right column • Why three- and four-valued ordering logic don’t work • The four principles of normalization • Relations vs. objects • Problems of duplicate rows If you’re a database professional, you owe it to yourself to be familiar with all of these topics. The trouble is, many of them, though crucially important, involve subtleties and depths whose consequences aren’t always immediately apparent. For example, relational theory prohibits left-to-right column ordering, as I’m sure you know—but have you ever thought through the practical implications of violating that prohibition? In such cases (and indeed all throughout the book), I’ve done my best to spell out the implications, and ramifications, in as clear a manner as possible. After all, database management is one field where there’s some solid theory to base our practice on; sadly, however, that theory is often dismissed (by people who ought to know better) as irrelevant to the “real world.” True database professionals should understand that theory and be ready to defend it when necessary. The book is based in large part on experience gained in teaching and dis- cussing the material in live seminars over a period of many years. Overall, it represents my current best thinking on a variety of relational matters, matters that are of both theoretical and practical significance. I hope you enjoy it. C. J. Date C. J. Date is an independent author, lecturer, researcher, and consultant, specializing in relational database tech- nology (a field he helped pioneer). He is best known for his book An Introduction to Database Systems, 8th Edition (Addison-Wesley, 2004), which has sold over 750,000 copies and is used by several hundred colleges and universities worldwide. He is also the author of many other books on relational database management, including most recently The Relational Database Dictionary (O’Reilly Media Inc., 2006). He was inducted into the Computing Industry Hall of Fame in 2004. Shelve in Databases User level: Intermediate–Advanced www.apress.com forums.apress.com FOR PROFESSIONALS BY PROFESSIONALS ™ Join online discussions: THE APRESS ROADMAP Mastering Oracle SQL and SQL*Plus The Programmer’s Guide to SQL Data Modeling for Everyone Date on Database: Writings 2000–2006 Date on Database Writings 2000–2006 Date ISBN 1-59059-746-X 9 781590 597460 90000 6 89253 59746 0 Companion eBook Available Companion eBook See last page for details on $10 eBook version www.it-ebooks.info Date on Database Writings 2000–2006 ■■■ C. J. Date Date_746-XFRONT.fm Page i Monday, October 16, 2006 4:30 PM www.it-ebooks.info Date on Database: Writings 2000–2006 Copyright © 2006 by C. J. Date All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher. ISBN-13 (pbk): 978-1-59059-746-0 ISBN-10 (pbk): 1-59059-746-X Printed and bound in the United States of America 9 8 7 6 5 4 3 2 1 Trademarked names may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, we use the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. Lead Editor: Jonathan Gennick Editorial Board: Steve Anglin, Ewan Buckingham, Gary Cornell, Jason Gilmore, Jonathan Gennick, Jonathan Hassell, James Huddleston, Chris Mills, Matthew Moodie, Dominic Shakeshaft, Jim Sumser, Keir Thomas, Matt Wade Project Manager: Tracy Brown Collins Copy Edit Manager: Nicole LeClerc Assistant Production Director: Kari Brooks-Copony Production Editor: Kelly Winquist Compositor: Susan Glinert Proofreader: Lori Bring Indexer: C. J. Date Cover Designer: Kurt Krames Manufacturing Director: Tom Debolski Distributed to the book trade worldwide by Springer-Verlag New York, Inc., 233 Spring Street, 6th Floor, New York, NY 10013. Phone 1-800-SPRINGER, fax 201-348-4505, e-mail orders-ny@springer-sbm.com, or visit http://www.springeronline.com. For information on translations, please contact Apress directly at 2560 Ninth Street, Suite 219, Berkeley, CA 94710. Phone 510-549-5930, fax 510-549-5939, e-mail info@apress.com, or visit http://www.apress.com. The information in this book is distributed on an “as is” basis, without warranty. Although every precaution has been taken in the preparation of this work, neither the author(s) nor Apress shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in this work. Date_746-XFRONT.fm Page ii Monday, October 16, 2006 4:30 PM www.it-ebooks.info Dedicated to the memory of John Lennon and George Harrison  Treason doth never prosper, what’s the reason? For if it prosper, none dare call it treason. —Sir John Harington Date_746-XFRONT.fm Page iii Monday, October 16, 2006 4:30 PM www.it-ebooks.info Date_746-XFRONT.fm Page iv Monday, October 16, 2006 4:30 PM www.it-ebooks.info v Contents at a Glance About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxv PART 1 ■ ■ ■ Some Preliminaries ■CHAPTER 1 Edgar F. Codd: A Tribute and Personal Memoir . . . . . . . . . . . . . . . . . 3 ■CHAPTER 2 An Interview with Chris Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 ■CHAPTER 3 Good Writing Does Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 PART 2 ■ ■ ■ And Now for Something Completely Different ■CHAPTER 4 On the Notion of Logical Difference . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 ■CHAPTER 5 On the Logical Difference Between Model and Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 ■CHAPTER 6 On the Logical Differences Between Types, Values, and Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 PART 3 ■ ■ ■ Relational Database Management ■CHAPTER 7 Why We Need Type BOOLEAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 ■CHAPTER 8 What First Normal Form Really Means . . . . . . . . . . . . . . . . . . . . . . . 107 ■CHAPTER 9 A Sweet Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 ■CHAPTER 10 Double Trouble, Double Trouble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 ■CHAPTER 11 Multiple Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 ■CHAPTER 12 Data Redundancy and Database Design . . . . . . . . . . . . . . . . . . . . . . 217 ■CHAPTER 13 Data Redundancy and Database Design: Further Thoughts Number One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255 Date_746-XFRONT.fm Page v Monday, October 16, 2006 4:30 PM www.it-ebooks.info vi ■CHAPTER 14 Tree-Structured Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 ■CHAPTER 15 Twelve Rules for Business Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 PART 4 ■ ■ ■ SQL Database Management ■CHAPTER 16 Two Remarks on SQL’s UNION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 ■CHAPTER 17 A Cure for Madness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 ■CHAPTER 18 Why Three- and Four-Valued Logic Don’t Work . . . . . . . . . . . . . . . 329 PART 5 ■ ■ ■ Further Relational Misconceptions ■CHAPTER 19 There’s Only One Relational Model . . . . . . . . . . . . . . . . . . . . . . . . . . 345 ■CHAPTER 20 The Relational Model Is Very Much Alive! . . . . . . . . . . . . . . . . . . . . 361 ■CHAPTER 21 What Do You Mean, “Post-Relational”? . . . . . . . . . . . . . . . . . . . . . . 369 ■CHAPTER 22 A Database Disconnect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 PART 6 ■ ■ ■ Subtyping and Inheritance ■CHAPTER 23 Is a Circle an Ellipse? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389 ■CHAPTER 24 What Does Substitutability Really Mean? . . . . . . . . . . . . . . . . . . . . . 409 PART 7 ■ ■ ■ Relational vs. Nonrelational Systems ■CHAPTER 25 Models, Models, Everywhere, Nor Any Time to Think . . . . . . . . . . 437 ■CHAPTER 26 Basic Concepts in UML: A Request for Clarification . . . . . . . . . . . 445 ■CHAPTER 27 A Comparison Between ODMG and The Third Manifesto . . . . . . . 457 ■CHAPTER 28 An Overview and Analysis of Proposals Based on the TSQL2 Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481 ■APPENDIX The Role of the Trade Press in Educating the Professional Community: A Case Study . . . . . . . . . . . . . . . . . . . . . . 515 ■INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527 Date_746-XFRONT.fm Page vi Monday, October 16, 2006 4:30 PM www.it-ebooks.info vii Contents About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxv PART 1 ■ ■ ■ Some Preliminaries ■CHAPTER 1 Edgar F. Codd: A Tribute and Personal Memoir . . . . . . . . . . . 3 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Database Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Other Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Personal Memories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 ■CHAPTER 2 An Interview with Chris Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 ■CHAPTER 3 Good Writing Does Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Preamble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Exhibit A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Restriction Conditions in DB2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 A Suggested Replacement for Exhibit A . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Exhibit B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Exhibit C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Date_746-XFRONT.fm Page vii Monday, October 16, 2006 4:30 PM www.it-ebooks.info viii ■CONTENTS PART 2 ■ ■ ■ And Now for Something Completely Different ■CHAPTER 4 On the Notion of Logical Difference . . . . . . . . . . . . . . . . . . . . . . 35 Preamble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Why Is It Important to Think Precisely? . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Logical Differences Are Big Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Some Things Are Much the Same . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Object Orientation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 The Unified Modeling Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Miscellaneous Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Appendix A: Some Quotes from the Literature . . . . . . . . . . . . . . . . . . . . . 43 ■CHAPTER 5 On the Logical Difference Between Model and Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Terms and Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 What Are Models For? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Definitions from the Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Examples of Confusion: Performance Issues . . . . . . . . . . . . . . . . . . . . . . . 55 Examples of Confusion: Many Different Data Structures . . . . . . . . . . . . . 58 Examples of Confusion: Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Examples of Confusion: Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Consequences of Such Confusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 ■CHAPTER 6 On the Logical Differences Between Types, Values, and Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Types Are Fundamental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 More on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Values and Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Values and Variables Can Be Arbitrarily Complex . . . . . . . . . . . . . . . . . . . 77 Variables Are Updatable, Values Aren’t . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Date_746-XFRONT.fm Page viii Monday, October 16, 2006 4:30 PM 6419de0a79232b3f3c7e0b078da09b55 www.it-ebooks.info ■CONTENTS ix Pseudovariables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Variables Have Addresses, Values Don’t . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Relation Values and Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Examples of Confusion: Values vs. Variables . . . . . . . . . . . . . . . . . . . . . . 87 Logical Sameness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 A Hypothesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Examples of Confusion: Types vs. Values and/or Variables . . . . . . . . . . . 92 Consequences of Such Confusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 PART 3 ■ ■ ■ Relational Database Management ■CHAPTER 7 Why We Need Type BOOLEAN . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 ■CHAPTER 8 What First Normal Form Really Means . . . . . . . . . . . . . . . . . . 107 Some Preliminaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 “Data Value Atomicity” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Relation-Valued Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Domains Can Contain Anything! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Relation-Valued Attributes Make Outer Join Unnecessary . . . . . . . . . . . 116 Relation-Valued Attributes in Base Tables?—The Bad News . . . . . . . . 118 Relation-Valued Attributes in Base Tables?—The Good News . . . . . . . 121 A Remark on “NF² Relations” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 A Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Appendix A: Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Appendix B: The Information Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Appendix C: Definitions from the Literature . . . . . . . . . . . . . . . . . . . . . . . 135 Appendix D: So What About “Multi-Value Systems”? . . . . . . . . . . . . . . 136 Appendix E: Formal Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 ■CHAPTER 9 A Sweet Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 SQL Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 The “Select * ” Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 Duplicate Column Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Missing Column Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Date_746-XFRONT.fm Page ix Monday, October 16, 2006 4:30 PM www.it-ebooks.info [...]... relation variables of such generated relation types 4 A relational assignment operation for assigning relation values to such relation variables 5 An open-ended collection of generic relational operators (“the relational algebra”) for deriving relation values from other relation values Let me conclude this section by observing that Ted’s work on the relational model didn’t just set the entire field of database. .. O’Reilly: Database in Depth: Relational Theory for Practitioners (2005) • From Addison-Wesley: Databases, Types, and the Relational Model: The Third Manifesto (3rd edition, coauthored with Hugh Darwen, 2006) • From O’Reilly: The Relational Database Dictionary (2006) Another book, Go Faster! The TransRelationalt™ Approach to DBMS Implementation, is due for publication in the near future Mr Date was inducted... than one introduces complexity, but no additional power As a matter of fact, it’s the concept of essentiality that forms the underpinning for the wellknown, and important, Information Principle: The entire information content of a relational database is represented in one and only one way: namely, as attribute values within tuples within relations I heard Ted refer to this principle on more than one... www.it-ebooks.info xvii Date_ 746-XFRONT.fm Page xviii Monday, October 16, 2006 4:30 PM www.it-ebooks.info Date_ 746-XFRONT.fm Page xix Monday, October 16, 2006 4:30 PM About the Author ■ J DATE is an independent author, lecturer, researcher, and consultant, specializing in relational C database technology He is best known for his book An Introduction to Database Systems (8th edition, Addison-Wesley, 2004),... 340 Some Questions of Intuition 340 www.it-ebooks.info xiii Date_ 746-XFRONT.fm Page xiv Monday, October 16, 2006 4:30 PM xiv ■C O N T E N T S PART 5 ■■■ Further Relational Misconceptions ■CHAPTER 19 There’s Only One Relational Model 345 Celko’s Preamble 347 “Chris Date = No Duplicates, No... data—namely, by means of relations themselves—and the sole essential information carriers in a relational database are thus necessarily relations, a fortiori By contrast, other data models typically provide many distinct ways to represent data (lists, bags, links, sets, arrays, and so on) , and all or any of those ways can be used as essential information carriers in a nonrelational database One way of representing... www.it-ebooks.info Date_ 746-XFRONT.fm Page xiii Monday, October 16, 2006 4:30 PM ■C O N T E N T S PART 4 ■■■ SQL Database Management ■CHAPTER 16 Two Remarks on SQL’s UNION 313 UNION in the Relational Model 313 Data Type Conversion 314 Duplicate Rows 315 Concluding... permission of Fabian Pascal Why Three- and Four-Valued Logic Don’t Work Originally published on the website http://www.dbdebunk.com (February 2006) Reprinted by permission of Fabian Pascal There’s Only One Relational Model Originally published on the website http://www.dbdebunk.com (February 2001) Reprinted by permission of Fabian Pascal The Relational Model Is Very Much Alive! Originally published on the... 2: And Now for Something Completely Different Part 3: Relational Database Management Part 4: SQL Database Management Part 5: Further Relational Misconceptions Part 6: Subtyping and Inheritance Part 7: Relational vs Nonrelational Systems Each part has its own introduction, and I’ll leave further details of individual papers to those introductions There’s also an appendix, documenting my experience (such... permission of O’Reilly Media, Inc and Tony Williams Good Writing Does Matter Originally published in two parts as Commentary in the Business Rules Journal on the website http://www.BRCommunity.com (February and April 2002) Reprinted by permission of Business Rule Solutions, Inc xix www.it-ebooks.info Date_ 746-XFRONT.fm Page xx Monday, October 16, 2006 4:30 PM xx ■A B O U T T H E A U T H O R On the Notion . details on $10 eBook version www.it-ebooks.info Date on Database Writings 2000–2006 ■■■ C. J. Date Date_746-XFRONT.fm Page i Monday, October 16, 2006 4:30 PM www.it-ebooks.info Date on Database: . Modeling for Everyone Date on Database: Writings 2000–2006 Date on Database Writings 2000–2006 Date ISBN 1-59059-746-X 9 781590 597460 90000 6 89253 59746 0 Companion eBook Available Companion eBook See. the reason? For if it prosper, none dare call it treason. —Sir John Harington Date_ 746-XFRONT.fm Page iii Monday, October 16, 2006 4:30 PM www.it-ebooks.info Date_ 746-XFRONT.fm Page iv Monday,