SETS AND NEGATION IN A LOGIC DATABASE LANGUAGE (LDL1).

Catrie Beeri*, Shamim Naqvi, Raghu Ramakrishnan, Oded Shmueli, Shalom Tsur

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

87 Scopus citations

Abstract

In this paper we extend LDL, a Logic Based Database Language, to include finite sets and negation. The new language is called LDL1. We define the notion of a model and show that a negation-free program need not have a model, and that it may have more than one minimal model. We impose syntactic restrictions in order to define a deterministic language. These restrictions allow only layered (stratified) programs. We prove that for any program satisfying the syntactic restrictions of layering, there is a minimal model, and that this model can be constructed in a bottom-up fashion. Extensions to the basic grouping mechanism are proposed. We show that these extensions can be translated into equivalent LDL1 programs. Finally, we show how the technique of magic sets can be extended to translate LDL1 programs into equivalent programs which can often be executed more efficiently.

Original languageEnglish
Title of host publicationUnknown Host Publication Title
PublisherACM
Pages21-37
Number of pages17
ISBN (Print)0897912233, 9780897912235
DOIs
StatePublished - 1987
Externally publishedYes

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