Foundation for Future Database Systems: The Third Manifesto - Softcover

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C. J. Date is an independent author, lecturer, researcher, and consultant specializing in relational database systems, a field he helped pioneer. Among other projects, he was involved in technical planning for the IBM products SQL/DS and DB2. He is best known for his books, in particular, An Introduction to Database Systems (7th edition, Addison-Wesley, 2000), the standard text in the field, which has sold well over half a million copies worldwide. Mr. Date is widely acknowledged for his ability to explain complex technical material in a clear and understandable fashion.

Hugh Darwen has been involved in software development since 1967 as an employee of IBM United Kingdom, Ltd. He has been active in the relational database arena since 1978. He was one of the chief architects and developers of an IBM relational product called Business System 12, a product that faithfully embraced the principles of the relational model. He has been an active participant in the development of SQL international standards since 1988.

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A detailed study of the impact of objects and type theory on the relational model of data, including a comprehensive model of type inheritance!

"This book should be recommended reading for software engineers, database designers, graduate students, undergraduate students, data modelers--for just about anybody with a serious interest in database technology."
--Declan Brady, MBCS, Lead Systems Architect, ICL

"As a database application designer/architect, I'm interested in ideals as well as in currently available tools . . . This book is a rich source of worthy ideals. In particular, it provides good coverage of areas where SQL, and much commercial Object Orientation training material, are found lacking."
--Tom Pledger, Peace International Software

Foundation for Future Database Systems: The Third Manifesto is a proposal for the future direction of data and database management systems (DBMSs). It consists of a precise, formal definition of an abstract model of data, to be considered as a blueprint for the design of a DBMS and a database language. Among other things, it provides a rock-solid foundation for integrating relational and object technologies.

The proposed foundation represents an evolutionary step, not a revolutionary one; it builds on Codd's relational model of data and on the research that sprang from that work. It also incorporates a precise and comprehensive specification for a method of defining data types, including a comprehensive model of type inheritance, to address a lack that has been observed by many authorities; thus, it also builds on research in the field of object orientation. With a sound footing in both camps of the object/relational divide, therefore, the Manifesto is offered as a firm foundation for the DBMSs of the future.

Significant features of this new edition include:

• Major extensions to the inheritance model
• Significantly improved language proposals
• Improved discussions of read-only vs. update operators, selectors, THE_ operators, tuple types vs. possible representations, grouping and ungrouping, first normal form, assignment, constraints, predicates, and many other topics
• All SQL discussions upgraded to the level of the new SQL:1999 standard
• Several new appendixes

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Preface The fact that the second edition of this book appears so hot on the heels of its predecessor clearly requires some explanation. In fact, there were several reasons why we felt it desirable to revise the book so soon, but the overriding one had to do with our model of type inheritance. To be specific, the version of the model described in the first edition has been so considerably--though, for the most part, compatibly--extended and improved that we now regard it as a part (albeit an optional part) of the Manifesto itself. In the first edition, it was presented merely as a set of somewhat tentative "proposals," with no very definite connection to the Manifesto proper; now, by contrast, we present it as a set of firm prescriptions, and we require a DBMS that supports the ideas of the Manifesto, if it supports type inheritance at all, to support our own inheritance model specifically. Because of these (evolutionary!) changes to our inheritance model, Part IV of the book in particular has been completely rewritten. However, we have naturally taken the opportunity to make numerous changes throughout the rest of the text as well, including many clarifications and other improvements and--we regret to have to say--a few corrections also. Here is an overview of those changes: Chapter 1: The distinctions "value vs. variable" and "value vs. appearance vs. encoding" have been clarified. Chapter 2: Certain aspects of the examples--especially the "wrong equation" example--have been amplified. Chapter 3: OO Prescriptions 2 and 3 have been combined and revised to bring them into line with our new inheritance model. RM Prescription 24 and OO Proscription 2 have also been revised (actually tightened up). Several of the prescriptions, proscriptions, and suggestions have been reworded. Chapter 4: Has been extended to show that is not primitive. Chapter 5: Many revisions, simplifications, and extensions have been made to the syntax of Tutorial D. In particular, the treatment of type constraints has been improved. Corrections have been made to some of the mappings. Chapter 6: Extensively revised throughout. In particular, the discussions of read-only vs. update operators, selectors, THE_ operators, tuple types vs. possible representations, grouping and ungrouping, first normal form, equivalent possible representations, multiple assignment, type constraints, database constraints, and relvar and database predicates have all been clarified or corrected or both. Chapter 7: Minor clarifications. Chapter 8: As noted under Chapter 3 above, OO Prescriptions 2 and 3 have been combined and revised. Other minor clarifications have also been made. Chapter 9: As noted under Chapter 3 above, OO Proscription 2 has been revised. Chapter 10: Extensions and corrections have been made to the treatment of foreign keys (RM Very Strong Suggestion 2) and quota queries (RM Very Strong Suggestion 5). RM Very Strong Suggestion 7 has been revised and clarified. The treatment of SQL migration (RM Very Strong Suggestion 9) has been extended to take the new features of SQL:1999 into account. Chapter 11: Minor clarifications. Chapters 12-16: Completely restructured and rewritten (as already explained). Appendix A: Minor clarifications. Appendix B: New (an extended discussion of "the two great blunders"). Appendix C (old Appendix B): Minor clarifications. Appendix D: New (a discussion of types and units). Appendix E (old Appendix D): Minor clarifications. Appendix F: New (a discussion of the possibility--and undesirability--of changing the semantics of inherited operators and related matters, with worked examples). Appendix G (old Appendix C): Completely rewritten, and considerably expanded. Appendix H (old Appendix E): Updated to reflect the new SQL standard ("SQL:1999"). Appendix I (old Appendix F): Minor clarifications. Appendix J (old Appendix G): Minor clarifications. Appendix K (old Appendix H): Several new annotated references. Revised throughout. In addition to the above, we have of course made numerous cosmetic changes throughout the book. Also, we have taken the opportunity to make a small but significant change to the book's overall title. The title of the first edition characterized the Manifesto as a "foundation for object/relational databases." While that characterization was accurate as far as it went, it did not really go far enough. Rather, we now regard (and in fact always did regard) the Manifesto as a foundation for future databases in general--including, for example, databases that contain temporal data and databases that are used in connection with the World Wide Web. Moreover, we also regard it as a good foundation on which to build rule engines (also known as business logic servers), which, as one of us has tried to show in another recent book,* are exactly what the next generation of DBMSs really ought to be.