There is a growing interest in integrating databases and programming languages. In recent years the programming language community has developed new models of computation such as logic programming, object-oriented programming and functional programming, to add to the well established von Neumann model. The data base community has almost independently developed more and more sophisticated data models to solve the problems of large scale data organisation. To make use of these new models in programming languages there must be an awareness of the problems of large scale data. The data base designers can also learn much about language interfaces from programming language designers. The purpose of this book is to present the state of the art in integrating both approaches. The book evolved from the proceedings of a workshop held at the Appin in August 1985. It consists of three sections. The first, "Data Types and Persistence," discusses the issues of data abstraction in a persistent environment. Type systems, modules and binding mechanisms that are appropriate for programming in the large are proposed. Type checking for polymorphic systems and across innovations of the type checker are also discussed. The second section, "Database Types in Programming Languages," introduces the concept of inheritance as a method of polymorphic modelling. It is shown how inheritance can be used as a method of computation in logic programming and how it is appropriate for modelling large scale data in databases. The last section discusses the issues of controlled access to large scale data in a concurrent and distributed persistent environment. Finally methods of how we may implement persistence and buildmachine architectures for persistent data round off the book.

There is an established interest in integrating databases and programming languages. This book on Data Types and Persistence evolved from the proceedings of a workshop held at the Appin in August 1985. The purpose of the Appin workshop was to focus on these two aspects: persistence and data types, and to bring together people from various disciplines who have thought about these problems. Particular topics of"interest include the design of type systems appropriate for database work, the representation of persistent objects such as data types and modules, and the provision of orthogonal persistence and certain aspects of transactions and concurrency. The programme was broken into three sessions: morning, late afternoon and evening to allow the participants to take advantage of two beautiful days in the Scottish Highlands. The financial assistance of the Science and Engineering Research Council, the National Science Foundation and International Computers Ltd. is gratefully acknowledged. We would also like to thank Isabel Graham, Anne Donnelly and Estelle Taylor for their help in organising the workshop. Finally our thanks to Pete Bailey, Ray Carick and Dave Munro for the immense task they undertook in typesetting the book. The convergence of programming languages and databases to a coherent and consistent whole requires ideas from, and adjustment in, both intellectual camps. The first group of chapters in this book present ideas and adjustments coming from the programming language research community. This community frequently discusses types and uses them as a framework for other discussions.

Databaseresearchisa?eldofcomputersciencewheretheorymeetsapplications. Many concepts and methods, that were regarded as issues of theoretical interest when initially proposed, are now included in implemented database systems and related products. Examples abound in the ?elds of database design, query languages, query optimization, concurrency control, statistical databases, and many others. The papers contained in this volume were presented at ICDT 99, the 7th - ternationalConferenceonDatabaseTheory, inJerusalem, Israel, January10 12, 1999. ICDT is an international forum for research on the principles of database systems. It is a biennial conference, and has a tradition of being held in beau- ful European sites: Rome in 1986, Bruges in 1988, Paris in 1990, Berlin in 1992, Prague in 1995, and Delphi in 1997. From 1992, ICDT has been merged with another series of conferences on theoretical aspects of database systems, The Symposium on Mathematical Fundamentals of Database Systems (MFDBS), that was initiated in Dresden (1987), and continued in Visegrad (1989) and Rostock (1991). ICDT aims to enhance the exchange of ideas and cooperation in database research both within uni?ed Europe, and between Europe and the other continents. ICDT 99 was organized in cooperation with: ACM Special Interest Group on Management of Data (Sigmod) IEEE Israel Chapter ILA The Israel Association for Information Processing EDBT Foundation ICDT 99 was sponsored by: The Hebrew University of Jerusalem Tel Aviv University Tandem Labs Israel, a Compaq Company This volume contains 26 technical papers selected from 89 submissions."