A Database Interface for Complex Objects

Marcel Holsheimer, Rolf A. de By, R.A. de By, Hassan Ait-Kaci

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We describe a formal design for a logical query language using psi-terms as data structures to interact effectively and efficiently with a relational database. The structure of psi-terms provides an adequate representation for so-called complex objects. They generalize conventional terms used in logic programming: they are sorted attributed structures, ordered thanks to a subsort ordering. Unification of psi-terms is an effective means for integrating multiple inheritance and partial information into a deduction process. We define a compact database representation for psi-terms, representing part of the subsorting relation in the database as well. We describe a retrieval algorithm based on an abstract interpretation of the psi-term unification process and prove its formal correctness. This algorithm is efficient in that it incrementally retrieves only additional facts that are actually needed by a query, and never retrieves the same fact twice.
Original languageUndefined
Title of host publicationProceedings of the 11th International Conference on Logic Programming (ICLP 1994)
Place of PublicationCambridge, MA, USA
PublisherMIT Press
Number of pages19
ISBN (Print)0-262-72022-1
Publication statusPublished - Jun 1994
Event11th International Conference on Logic Programming, ICLP 1994 - Santa Margherita Ligure, Italy
Duration: 13 Jun 199418 Jun 1994

Publication series

PublisherMIT Press


Conference11th International Conference on Logic Programming, ICLP 1994
Other13-18 June 1994


  • IR-66446
  • EWI-7259
  • METIS-119760

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