Active integrity constraints

Abstract

In this paper we deal with inconsistent databases and propose a logic framework that allows specifying sets of actions which should be performed to make databases consistent (repairs). The motivation of this work stems from the observation that in repairing a database it is natural to express among a set of update operations, the (preferred) actions which should be performed to repair the database. We introduce (conditioned) active integrity constraints, a simple and powerful form of active rules with declarative semantics, well suited for computing database repairs and consistent answers. We first consider a "prescriptive" semantics where the allowed actions are those specified by the constraints. Under such a semantics the existence of repairs and consistent answers is not guaranteed. Thus, we also investigate the class of universally quantified constraints under a different semantics where actions are interpreted as preference conditions on the set of possible repairs ("preferable" semantics). Under such a semantics every database with integrity constraints admits repairs and consistent answers. We show that (conditioned) active integrity constraints can be rewritten into disjunctive Datalog programs with classical negation and that (preferred) repairs can be derived through the computation of (preferred) disjunctive stable models. We study the complexity of computing repairs and consistent answers and show that active integrity constraints can also be used to express hard problems. * The author is also supported by ICAR-CNR and Exeura S.r.l.

Integrity Constraints for General-Purpose Knowledge Bases

“…Integrity constraints in relational databases can be written as first-order formulas in denial clausal form [21] -which are essentially equivalent in form to bridge rules with no head. We can see any database DB as a single-context MCS consisting of exactly the context Ctx(DB); we will also denote this MCS by Ctx(DB), as this poses no ambiguity.…”

A Dynamic View of Active Integrity Constraints

“…Active integrity constraints were proposed about ten years ago [FGZ04], and various ways of repairing a database V by such constraints have been studied in the literature. We refer to [CT11] for an overview.…”

Active Integrity Constraints for Multi-context Systems

“…In this paper, we address the problem of computing repairs by combining two ideas: clausal-form integrity constraints for multi-context systems (MCSs) [11] and active integrity constraints (AICs) for relational databases [16]. We demonstrate the expressiveness of our formalism and show how it can be used to compute repairs for inconsistent MCSs in general, and for ontologies, in particular.…”

“…In[16], existentially quantified variables can also occur in negative literals. This was not discussed in subsequent work, and we ignore it for simplicity of presentation 2.…”