Readers familiar with the three prior volumes of database guru Chris Date's Relational Database Writings series will need no further recommendation. The fourth volume compiles Date's authoritative columns, articles, and papers on various aspects of relational technology--spanning the years 1991 to 1994.

Fifty years of relational. It’s hard to believe the relational model has been around now for over half a century! But it has—it was born on August 19th, 1969, when Codd’s first database paper was published. And Chris Date has been involved with it for almost the whole of that time, working closely with Codd for many years and publishing the very first, and definitive, book on the subject in 1975. In this book’s title essay, Chris offers his own unique perspective (two chapters) on those fifty years. No database professional can afford to miss this one of a kind history. But there’s more to this book than just a little personal history. Another unique feature is an extensive and in depth discussion (nine chapters) of a variety of frequently asked questions on relational matters, covering such topics as mathematics and the relational model; relational algebra; predicates; relation valued attributes; keys and normalization; missing information; and the SQL language. Another part of the book offers detailed responses to critics (four chapters). Finally, the book also contains the text of several recent interviews with Chris Date, covering such matters as RM/V2, XML, NoSQL, The Third Manifesto, and how SQL came to dominate the database landscape.

A note from the authors: Dear Reader: "Database is boring." That sentiment is heard all too widely these days. But it's so wrong! The database field is full of important problems still to be solved and interesting issues still to be examined - and some of those problems and issues are explored in this book. Between us, we have nearly 80 years experience in this field, and we're still actively researching, exploring, and learning, as well as helping others do the same. The present book is the latest in a series devoted to these goals; using "The Third Manifesto" (a detailed proposal for the future of database technology) as a foundation, it reports on some of our most recent investigations in this field. Among many other things, it includes the most recent version of "The Third Manifesto" itself; specifications for a conforming language called Tutorial D; and a detailed proposal for a model of type inheritance. Other significant features include: - Extending the foreign key concept - Simplifying queries using image relations - Closer looks at logic and relational algebra - Suggested approaches to "missing information" - Responses to certain "Manifesto" criticisms - Clarifying aspects of normalization The tone of the book overall is naturally somewhat serious, but there are moments of light relief as well. We hope you enjoy it. C.J. Date and Hugh Darwen

The Database Relational Model: A Retrospective Review and Analysis is a retrospective of E.F. Codd's original ideas in which C.J. Date revisits the original papers, highlights their critical contributions to the basis of relational database management systems, and discusses the current day applications of these ideas. Codd's relational model, first presented to the world in a series of research papers from 1969 to 1979, was at the time revolutionary. More than 30 years later, however, it seems that the database community in general has come to regard the relational model as somewhat passe and no longer relevant, even though the entire database industry is founded on that model. Two factors that might explain this are that several of Codd's original papers have since become hard to find, and some of his writings were somewhat difficult to read and understand. This book aims to clearly evaluate Codd's original ideas and relate them to today's database society.

Joe Celkos SQL for Smarties: Advanced SQL Programming offers tips and techniques in advanced programming. This book is the fourth edition and it consists of 39 chapters, starting with a comparison between databases and file systems. It covers transactions and currency control, schema level objects, locating data and schema numbers, base tables, and auxiliary tables. Furthermore, procedural, semi-procedural, and declarative programming are explored in this book. The book also presents the different normal forms in database normalization, including the first, second, third, fourth, fifth, elementary key, domain-key, and Boyce-Codd normal forms. It also offers practical hints for normalization and denormalization. The book discusses different data types, such as the numeric, temporal and character data types; the different predicates; and the simple and advanced SELECT statements. In addition, the book presents virtual tables, and it discusses data partitions in queries; grouping operations; simple aggregate functions; and descriptive statistics, matrices and graphs in SQL. The book concludes with a discussion about optimizing SQL. It will be of great value to SQL programmers. - Expert advice from a noted SQL authority and award-winning columnist who has given ten years service to the ANSI SQL standards committee - Teaches scores of advanced techniques that can be used with any product, in any SQL environment, whether it is an SQL 92 or SQL 2008 environment - Offers tips for working around deficiencies and gives insight into real-world challenges

E. F. Codd’s relational model of data has been described as one of the three greatest inventions of all time (the other two being agriculture and the scientific method), and his receipt of the 1981 ACM Turing Award, the top award in computer science, for inventing it was thoroughly deserved. The papers in which Codd first described his model were staggering in their originality; they had, and continue to have, a huge impact on just about every aspect of the way we do business in the world today. And yet few people, even in the professional database community, are truly familiar with those papers. This book—a thorough overhaul and rewrite of an earlier book by the same name—is an attempt to remedy this sorry state of affairs. In it, well known author C. J. Date provides a detailed examination of all of Codd’s major database publications, explaining the nature of his contribution in depth, and in particular highlighting not only the many things he got right but also some of the things he got wrong. Database theory and practice have evolved considerably since Codd first defined his relational model, back in 1969. This book draws on decades of experience to present the most up to date treatment of the material possible. Anyone with a professional interest in databases can benefit from the insights it contains. The book is product independent.

A review of relational concepts -- An overview of Tutorial D -- Time and the database -- What is the problem? -- Intervals -- Operators on intervals -- The EXPAND and COLLAPSE operators -- The PACK and UNPACK operators -- Generalizing the relational operators -- Database design -- Integrity constraints 1 : candidate keys and related constraints -- Integrity constraints 2 : general constraints -- Database queries -- Database updates -- Stated times and logged times -- Point and interval types revisited.

C. J. Date is one of the founding fathers of the relational database field. Many of today’s seasoned database professionals "grew up" on Date’s writings. Those same professionals, along with other serious database students and practitioners, form the core audience for Date’s ongoing writing efforts. Date on Database: Writings 2000-2006 is a compilation of Date’s most significant articles and papers over the past seven years. It gives readers a one-stop place in which to find Date’s latest thinking on relational technology. Many papers are not easily found outside this book.

What makes this book different from others on database design? Many resources on design practice do little to explain the underlying theory, and books on design theory are aimed primarily at theoreticians. In this book, renowned expert Chris Date bridges the gap by introducing design theory in ways practitioners can understand—drawing on lessons learned over four decades of experience to demonstrate why proper database design is so critical in the first place. Every chapter includes a set of exercises that show how to apply the theoretical ideas in practice, provide additional information, or ask you to prove some simple theoretical result. If you’re a database professional familiar with the relational model, and have more than a passing interest in database design, this book is for you. Questions this book answers include: Why is Heath’s Theorem so important? What is The Principle of Orthogonal Design? What makes some JDs reducible and others irreducible? Why does dependency preservation matter? Should data redundancy always be avoided? Can it be? Databases often stay in production for decades, and careful design is critical for avoiding subtle errors and processing problems over time. If they’re badly designed, the negative impacts can be incredibly widespread. This gentle introduction shows you how to use important theoretical results to create good database designs.

SQL is full of difficulties and traps for the unwary. You can avoid them if you understand relational theory, but only if you know how to put the theory into practice. In this insightful book, author C.J. Date explains relational theory in depth, and demonstrates through numerous examples and exercises how you can apply it directly to your use of SQL. This second edition includes new material on recursive queries, “missing information” without nulls, new update operators, and topics such as aggregate operators, grouping and ungrouping, and view updating. If you have a modest-to-advanced background in SQL, you’ll learn how to deal with a host of common SQL dilemmas. Why is proper column naming so important? Nulls in your database are causing you to get wrong answers. Why? What can you do about it? Is it possible to write an SQL query to find employees who have never been in the same department for more than six months at a time? SQL supports “quantified comparisons,” but they’re better avoided. Why? How do you avoid them? Constraints are crucially important, but most SQL products don’t support them properly. What can you do to resolve this situation? Database theory and practice have evolved since the relational model was developed more than 40 years ago. SQL and Relational Theory draws on decades of research to present the most up-to-date treatment of SQL available. C.J. Date has a stature that is unique within the database industry. A prolific writer well known for the bestselling textbook An Introduction to Database Systems (Addison-Wesley), he has an exceptionally clear style when writing about complex principles and theory.