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Journal of Logic and Computation, Volume 8, Issue 6, pp. 745-775: Abstract.

Update rules in datalog programs

MHF Alves1, D Laurent2 and N Spyratos3

1Universidade Federal do Parana, Departamento de Informatica, Centro Politecnico, Jardim das Americas, Caixa Postal 19081, Curitiba, 81531-990, Brazil, E-mail: mirian:inf.ufpr.br, 2Universite de Tours, LI/E3I - IUP GEII Info. & Telecom. 3, Place J. Jaures, F-41000 Blois, France, E-mail: laurent@univ@univ-tours.fr, 3Universite de Paris-Sud, LRI, U.R.A. 410 du CNRS, Bat. 490, F-91405 Orsay Cedex, France, E-mail: spyratos@lri.fr

We propose a deductive database model containing two kinds of rules: update rules of the form L0[larr] L1 are literals, and query rules of the form of normal logic program rules. A basic feature of our approach is that new knowledge inputs are always assimilated. Moreover, updates are always deterministic and they preserve database consistency.

We consider that update rules have higher priority than query rules, i.e., update rules may generate exceptions to query-driven derivations. We introduce a semantics framework for database update and query answering, based on the well-founded semantics. We also suggest an alternative approach based on extended logic programs and we show that our database model can be defined in terms of non-monotonic formalisms.

Keywords: Datalog, deductive database, update.

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