University of Pennsylvania ScholarlyCommons Technical Reports (CIS) Department of Computer & Information Science November 1988 Workshop on Database Programming Languages François Bancilhon Altaïr Peter Buneman University of Pennsylvania Follow this and additional works at: https://repository.upenn.edu/cis_reports Recommended Citation François Bancilhon and Peter Buneman, "Workshop on Database Programming Languages", . November 1988. University of Pennsylvania Department of Computer and Information Science Technical Report No. MS-CIS-88-93. This paper is posted at ScholarlyCommons. https://repository.upenn.edu/cis_reports/601 For more information, please contact [email protected]. Workshop on Database Programming Languages Abstract These are the revised proceedings of the Workshop on Database Programming Languages held at Roscoff, Finistère, France in September of 1987. The last few years have seen an enormous activity in the development of new programming languages and new programming environments for databases. The purpose of the workshop was to bring together researchers from both databases and programming languages to discuss recent developments in the two areas in the hope of overcoming some of the obstacles that appear to prevent the construction of a uniform database programming environment. The workshop, which follows a previous workshop held in Appin, Scotland in 1985, was extremely successful. The organizers were delighted with both the quality and volume of the submissions for this meeting, and it was regrettable that more papers could not be accepted. Both the stimulating discussions and the excellent food and scenery of the Brittany coast made the meeting thoroughly enjoyable. There were three main foci for this workshop: the type systems suitable for databases (especially object- oriented and complex-object databases,) the representation and manipulation of persistent structures, and extensions to deductive databases that allow for more general and flexible programming. Many of the papers describe recent results, or work in progress, and are indicative of the latest research trends in database programming languages. The organizers are extremely grateful for the financial support given by CRAI (Italy), Altaïr (France) and AT&T (USA). We would also like to acknowledge the organizational help provided by Florence Deshors, Hélène Gans and Pauline Turcaud of Altaïr, and by Karen Carter of the University of Pennsylvania. Comments University of Pennsylvania Department of Computer and Information Science Technical Report No. MS- CIS-88-93. This technical report is available at ScholarlyCommons: https://repository.upenn.edu/cis_reports/601 WORKSHOP ON DATABASE PROGRAMMING LANGUAGES Organizers: Peter Bunernan, University of Pennsylvania Francois Bancilhon, Altair Department of Computer and Information Science School of Engineering and Applied Science University of Pennsylvania Philadelphia, PA 19104 November 1988 WORKSHOP ON DATABASE PROGRAMMING LANGUAGES Organizers: Franqois Bancilhon ( Alt air) Peter Buneman (University of Pennsylvania) aided by: Serge Abi t eboul (INRIA) Rishiyur Nikhil (MIT) Atsushi Ohori (University of Pennsylvania) Domenico Sac& (CRAI) Michel Scholl (INRIA) Sponsors: Alt aYr CRAI Copies of these proceedings are available from Technical Report Center University of Pennsylvania Department of Computer and Information Science 200 South 33rd Street Philadelphia, PA 191046389 USA (cost $26.00, postage inc., within USA) and from A1 tair BP 105 - Roquencourt 78153 Le Chesnay ckdex France FOREWORD These are the revised proceedings of the Workshop on Database Programming Languages held at Roscoff, Finistkre, France in September of 1987. The last few years have seen an enormous activity in the development of new programming languages and new program- ming environments for databases. The purpose of the workshop was to bring together researchers from both databases and programming languages to discuss recent develop- ments in the two areas in the hope of overcoming some of the obstacles that appear to prevent the construction of a uniform database programming environment. The workshop, which follows a previous workshop held in Appin, Scotand in 1985, was extremely success- ful. The organizers were delighted with both the quality and volume of the submissions for this meeting, and it was regrettable that more papers could not be accepted. Both the stimulating discussions and the excellent food and scenery of the Brittany coast made the meeting thoroughly enjoyable. There were three main foci for this workshop: the type systems suitable for databases (especially object-oriented and complex-object databases,) the representation and manip- ulation of persistent structures, and extensions to deductive databases that allow for more general and flexible programming. Many of the papers describe recent results, or work in progress, and are indicative of the latest research trends in database programming lan- guages. The organizers are extremely grateful for the financial support given by CRAI (Italy), AltaYr (France) and AT&T (USA). We would also like to acknowledge the organizational help provided by Florence Deshors, Hhlkne Gans and Pauline Turcaud of Alta'ir, and by Karen Carter of the University of Pennsylvania. Franqois Bancilhon and Peter Buneman SESSION IV: OBJECT ORIENTED SYSTEMS AND PERSISTENCE Sharing, Persistence and Object Orientation: a Database Perspective ................... 181 Setrag Khoshafian and Patrick Valduriez (MCC) Polymorphic Names and Iterations .........................................................206 Malcolm Atkinson (University of Glasgow) Ron Morrison (University of St. Andrews) 02,An Object-Oriented Data Model ........................................................224 Christopher Le'cluse, Philippe Richard, Fernando Velez (GIP Altair) Can objects change type? Can type objects change? ...................................... 241 Stanley Zdonik (Brown University) Semantics for Transactions in Shared Object Worlds ...................................... 248 J. Eliot and B. Moss (University of Massachusetts) A Practical Language to provide Persistence and a Rich Typing System ................ 253 Deborah Baker, David Fisher and Jonathan C. Shultis (Incremental Systems Inc.) SESSION V: LOGIC Database Updates in Logic Programming ................................................ 269 Shamim Naqvi, Ravi Krishnamurthy (MCC) Control and Optimization in a Logic Based Language for Knowledge and Data Intensive Applications ........................................... 279 Ravi Krishnamurthy and Carlo Zaniolo (MCC) COL: A Logic-Based Language for Complex Objects ......................................301 Serge Abiteboul and Ste'phane Grumbach (INRIA - Itocquencourt) SESSION VI: DATABASE PROGRAMMING LANGUAGES Why Database Languages Are a Bad Idea .................................................. 334 David Maier (Oregon Graduate Center) Data and Knowledge Model: A Proposal ................................................... 345 Maurice Houstma and Peter Apers (University of Twente) The Semantics of Update in a FDBPL ...................................................... 365 Rishyur Nikhil (MIT) Towards a Formalism for Module Interconnection and Version Selection ......................................................................... 384 Richard Hull and Dean Jacobs (University of Southern California) A DML for Complex Objects ................................................................ 409 Michel Lacroix and M. Vanhoedenaghe (Philips Research Lab, Brussels) Construction and Calculus of Types for Database Systems David Stemple Tim Sheard Department of Computer and Information Science University of Massachusetts, Amherst, MA. 01003 October 22, 1987 Abstract Database systems should allow the construction of types for the kinds of complex objects used in modern applications such as design systems and artificial intelligence applications. In addition to complex structures, the type system should incorporate encapsulation and inheri- tance features appropriate to such applications. Furthermore, arbitrary constraint specification should be a feature of such a type system in order to bind the systems to the semantics of the occasion. Incorporating these features in a database system specification language must be done very carefully in order to produce a facility that I. can be used effectively by database system designers 2. can be implemented efficiently 3. supports the kind of mechanical reasoning required to satisfy 1. and 2. The ADABTPL system under development at the University of Massachusetts represents an attempt to provide the features and meet the requirements listed above. The ADABTPL type system is a crucial part of this effort and contains the following features: A type construction approach with embedded constraints Parametric polymorphic types = user-defined type constructor functions Encapsulated abstract data types Multiple inheritance Constraints specifiable on function input and checked at compile time (verified) on all calls Type conditions on type parameters In this paper we present the ADABTPL type features and concentrate on the motivations for choosing these features and for limiting certain capabilities such as recursive types and inheritance. 1 Introduction Database systems should allow the construction of types for the kinds of complex objects used in modern applications such as design systems and artificial intelligence applications. In addition to complex structures,