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    Querying incomplete data over extended ER schemata

    Calì, Andrea and Martinenghi, D. (2010) Querying incomplete data over extended ER schemata. Theory and Practice of Logic Programming 10 (S03), pp. 291-329. ISSN 1471-0684.

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    Since Chen's Entity-Relationship (ER) model, conceptual modeling has been playing a fundamental role in relational data design. In this paper we consider an extended ER (EER) model enriched with cardinality constraints, disjointness assertions, and is a relations among both entities and relationships. In this setting, we consider the case of incomplete data, which is likely to occur, for instance, when data from different sources are integrated. In such a context, we address the problem of providing correct answers to conjunctive queries by reasoning on the schema. Based on previous results about decidability of the problem, we provide a query answering algorithm that performs rewriting of the initial query into a recursive Datalog query encoding the information about the schema. We finally show extensions to more general settings.


    Item Type: Article
    Keyword(s) / Subject(s): Extended ER model, dependencies, chase, incomplete data
    School: Birkbeck Faculties and Schools > Faculty of Science > School of Computing and Mathematical Sciences
    Research Centres and Institutes: Birkbeck Knowledge Lab
    Depositing User: Sarah Hall
    Date Deposited: 10 May 2013 14:12
    Last Modified: 09 Aug 2023 12:33


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