Semantic representations and query languages for or-sets

  • Authors:
  • Leonid Libkin;Limsoon Wong

  • Affiliations:
  • -;-

  • Venue:
  • PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
  • Year:
  • 1993

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Abstract

Or-sets were introduced by Imielinski, Naqvi and Vadaparty for dealing with limited forms of disjunctive information in database queries. Independently, Rounds used a similar notion for representing disjunctive and conjunctive information in the context of situation theory. In this paper we formulate a query language with adequate expressive power for or-sets. Using the notion of normalization of or-sets, queries at the “structural” and “conceptual” levels are distinguished. Losslessness of normalization is established for a large class of queries. We have obtained upper bounds for the cost of normalization. An approach related to that of Rounds is used to provide semantics for or-sets.