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      Union-Types in Object-Oriented Schemas

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      proceedings-article
      Proceedings of the Fifth International Workshop on Database Programming Languages (DBPL-5)
      Database Programming Languages
      6-8 September 1995
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            Abstract

            In this paper we investigate union-types in object oriented IQL-like schemas. These types can be used to model null values, variant types and generalization classes. They make, however, deciding equivalence and subtyping more difficult. We will show that the complexity of these two problems is co-NP-complete and present complete sets of rules for deciding both problems. The combination of union-types and multiple inheritance makes it also harder to detect typing-conflicts in a schema. We will give an algorithm for deciding this and discuss its complexity. Furthermore, we will present an algorithm for detecting schemas that define types with a bounded number of values. Finally, an algorithm will be presented that verifies whether in a schema the type of a subclass specifies options that are forbidden by its superclasses.

            Content

            Author and article information

            Contributors
            Conference
            September 1995
            September 1995
            : 1-12
            Affiliations
            [0001]Dept. of Math. and Comp. Science

            Eindhoven University of Technology

            PO box 513, 5600 MB Eindhoven
            Article
            10.14236/ewic/DBPL1995.13
            8a8d0814-cbf7-40a0-aa16-7bae9c3858e3
            © Jan Hidders. Published by BCS Learning and Development Ltd. Proceedings of the Fifth International Workshop on Database Programming Languages, Gubbio, Umbria, Italy

            This work is licensed under a Creative Commons Attribution 4.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

            Proceedings of the Fifth International Workshop on Database Programming Languages
            DBPL-5
            5
            Gubbio, Umbria, Italy
            6-8 September 1995
            Electronic Workshops in Computing (eWiC)
            Database Programming Languages
            History
            Product

            1477-9358 BCS Learning & Development

            Self URI (article page): https://www.scienceopen.com/hosted-document?doi=10.14236/ewic/DBPL1995.13
            Self URI (journal page): https://ewic.bcs.org/
            Categories
            Electronic Workshops in Computing

            Applied computer science,Computer science,Security & Cryptology,Graphics & Multimedia design,General computer science,Human-computer-interaction

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