• An inside analysis of a genetic-programming based optimizer 

    Muntés Mulero, Víctor; Aguilar Saborit, Josep; Larriba Pey, Josep; Zuzarte, Calisto; Markl, Volker (Institute of Electrical and Electronics Engineers, 2006)
    Text en actes de congrés
    Accés obert
    The use of evolutionary algorithms has been proposed as a powerful random search strategy to solve the join order problem. Specifically, genetic programming used in query optimization has been proposed as an alternative ...
  • Horn query learning with multiple refinement 

    Sierra Santibáñez, Josefina; Santibáñez Velilla, Josefina (2008)
    Accés restringit per política de l'editorial
    In this paper we try to understand the heuristics that underlie the decisions made by the Horn query learning algorithm proposed in [1]. We take advantage of our explicit representation of such heuristics in order to ...
  • Query containment in entity SQL 

    Rull Fort, Guillem; Bernstein, Philip A.; Garcia dos Santos, Ivo; Katsis, Yannis; Melnik, Sergey; Teniente López, Ernest (2013)
    Comunicació de congrés
    Accés restringit per política de l'editorial
    We describe a software architecture we have developed for a constructive containment checker of Entity SQL queries defined over extended ER schemas expressed in Microsoft's Entity Data Model. Our application of interest ...
  • Updating DL-Lite ontologies through first-order queries 

    Giacomo, Giuseppe De; Oriol Hilari, Xavier; Rosati, Riccardo; Savo, Domenico Fabio (Springer, 2016)
    Text en actes de congrés
    Accés obert
    In this paper we study instance-level update in DL-LiteA, the description logic underlying the OWL 2 QL standard. In particular we focus on formula-based approaches to ABox insertion and deletion. We show that DL-LiteA, ...
  • Validation of mappings between schemas 

    Rull, Guillem; Farré Tost, Carles; Teniente López, Ernest; Urpí Tubella, Antoni (2007-06)
    Report de recerca
    Accés obert
    Mappings between schemas are key elements in several contexts such as data exchange, data integration, peer data management systems, etc. In all these contexts, the process of designing a mapping requires the participation ...