"Time and Relational Theory" provides an in-depth description of temporal database systems, which provide special facilities for storing, querying, and updating historical and future data. Traditionally, database management systems provide little or no special support for temporal data at all. This situation is changing because: Cheap storage enables retention of large volumes of historical data in data warehousesUsers are now faced with temporal data problems, and need solutions Temporal features have recently been incorporated into the SQL standard, and vendors have begun to add temporal support to their DBMS products

Based on the groundbreaking text "Temporal Data & the Relational Model" (Morgan Kaufmann, 2002) and new research led by the authors, "Time and Relational Theory" is the only book to offer a complete overview of the functionality of a temporal DBMS. Expert authors Nikos Lorentzos, Hugh Darwen, and Chris Date describe an approach to temporal database management that is firmly rooted in classical relational theory and will stand the test of time.

This book covers the SQL:2011 temporal extensions in depth and identifies and discusses the temporal functionality still missing from SQL.
Understand how the relational model provides an ideal basis for taming the complexities of temporal databases Learn how to analyze and evaluate commercial temporal products with this timely and important information Be able to use sound principles in designing and using temporal databases Understand the temporal support recently added to SQL with coverage of the new SQL features in this unique, accurate, and authoritative reference Appreciate the benefits of a truly relational approach to the problem with this clear, user friendly presentation

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