BIROn - Birkbeck Institutional Research Online

    On separability of ontological constraints

    Calì, Andrea and Console, M. and Frosini, R. (2012) On separability of ontological constraints. In: Freire, J. and Suciu, D. (eds.) Proceedings of the 6th Alberto Mendelzon International Workshop on Foundations of Data Management, Ouro Preto, Brazil, June 27-30, 2012. CEUR Workshop Proceedings 866. CEUR Workshop Proceedings, pp. 48-61.

    Full text not available from this repository.

    Abstract

    When data schemata are enriched with expressive constraints that aim at representing the domain of interest, in order to answer queries one needs to consider the logical theory consisting of both the data and the constraints. Query answering in such a context is called ontological query answering. Commonly adopted database constraints in this field are tuple-generating dependencies (TGDs) and equality- generating dependencies (EGDs). It is well known that their interaction leads to intractability or undecidability of query answering even in the case of simple subclasses. Several conditions have been found to guarantee separability, that is lack of interaction, between TGDs and EGDs. Separability makes EGDs (mostly) irrelevant for query answering and therefore often guarantees tractability, as long as the theory is satisfiable. In this paper we review the two notions of separability found in the literature, as well as several syntactic conditions that are sufficient to prove them. We then shed light on the issue of satisfiability checking, showing that under a sufficient condition called deep separability it can be done by considering the TGDs only. We show that, fortunately, in the case of TGDs and EGDs, separability implies deep separability. This result generalizes several analogous ones, proved ad hoc for particular classes of constraints. Applications include the class of sticky TGDs and EGDs, for which we provide a syntactic separability condition which extends the analogous one for linear TGDs; preliminary experiments show the feasibility of query answering in this case.

    Metadata

    Item Type: Book Section
    School: Birkbeck Schools and Departments > School of Business, Economics & Informatics > Computer Science and Information Systems
    Research Centre: Birkbeck Knowledge Lab
    Depositing User: Sarah Hall
    Date Deposited: 26 Apr 2013 08:58
    Last Modified: 02 Dec 2016 13:22
    URI: http://eprints.bbk.ac.uk/id/eprint/6484

    Statistics

    Downloads
    Activity Overview
    0Downloads
    147Hits

    Additional statistics are available via IRStats2.

    Archive Staff Only (login required)

    Edit/View Item Edit/View Item