Maximal state independent approximations to minimal real change

  • Authors:

  • Michael Dekhtyar;Alexander Dikovsky;Sergey Dudakov;Nicolas Spyratos

  • Affiliations:

  • Department of CS, Tver State University, 3 Zheljabova str., Tver 170013, Russia E-mail: Michael.Dekhtyar@tversu.ru;Université de Nantes, IRIN, 2, rue de la Houssinière, BP 92208, F 44322 Nantes Cedex 3, France E-mail: Alexandre.Dikovsky@irin.univ-nantes.fr and Keldysh Institute for A ...;Department of CS, Tver State University, 3 Zheljabova str., Tver 170013, Russia E-mail: Sergey.Dudakov@tversu.ru;Université de Paris-Sud, LRI, U.R.A. 410 du CNRS, Bât. 490, F-91405 Orsay Cedex, France E-mail: Nicolas.Spyratos@lri.fr

  • Venue:
  • Annals of Mathematics and Artificial Intelligence
  • Year:
  • 2001

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Abstract

This paper is devoted to the problem of consistency enforcement for logical databases. The enforcement methods we propose compute the minimal real change in a given DB state, which is sufficient to accomplish the input update and preserve the integrity constraints (IC). For IC expressed in the form of a generalized logic program, this problem is proven to be hard. Meanwhile, we show that it is solvable in linear time under partial interpretations. We propose a method of computing DB state independent correct expansions of the input update and simultaneous optimization of IC with respect to this expansion. We show that under partial interpretations, optimal pairs (greatest correct update expansion/simplest equivalent IC) always exist and can be incrementally computed in square time. This partial solution being correct with respect to the total interpretations, we use it as an approximation in the total case. Moreover, for the class of IC without negation in clause bodies, we prove that this approximation constitutes the optimal pair (greatest correct update expansion/simplest equivalent IC).