The consistency extractor system: Answer set programs for consistent query answering in databases

Caniupan, Monica; Bertossi, Leopoldo

doi:10.1016/j.datak.2010.01.005

Cited by 59 publications

(25 citation statements)

References 56 publications

(101 reference statements)

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“…Query programs can be evaluated using engines, such as DLV [13], for computing the stable models of disjunctive logic programs, a problem known to be Π p 2 -complete. Two systems that have implemented this approach are Infomix [25] and ConsEx [8,9]. The latter uses the magic sets method [5] to eliminate unnecessary rules and generate more compact query programs.…”

Section: Related Workmentioning

confidence: 99%

Efficient querying of inconsistent databases with binary integer programming

2013

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An inconsistent database is a database that violates one or more integrity constraints. A typical approach for answering a query over an inconsistent database is to first clean the inconsistent database by transforming it to a consistent one and then apply the query to the consistent database. An alternative and more principled approach, known as consistent query answering, derives the answers to a query over an inconsistent database without changing the database, but by taking into account all possible repairs of the database.In this paper, we study the problem of consistent query answering over inconsistent databases for the class for conjunctive queries under primary key constraints. We develop a system, called EQUIP, that represents a fundamental departure from existing approaches for computing the consistent answers to queries in this class. At the heart of EQUIP is a technique, based on Binary Integer Programming (BIP), that repeatedly searches for repairs to eliminate candidate consistent answers until no further such candidates can be eliminated. We establish rigorously the correctness of the algorithms behind EQUIP and carry out an extensive experimental investigation that validates the effectiveness of our approach. Specifically, EQUIP exhibits good and stable performance on conjunctive queries under primary key constraints, it significantly outperforms existing systems for computing the consistent answers of such queries in the case in which the consistent answers are not first-order rewritable, and it scales well.

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Section: Related Workmentioning

confidence: 99%

Efficient querying of inconsistent databases with binary integer programming

2013

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“…More specifically, techniques used in CQA, such as magic sets for stable model semantics (Faber et al 2007), and identification of predicates that are relevant to queries and constraints, could also be used in this setting. In this way, the number of rules and the amount of data that are needed to run the program are reduced (Caniupan and Bertossi 2010;Eiter et al 2008).…”

Section: Discussionmentioning

confidence: 99%

“…In (Caniupan and Bertossi 2010), the dependency graph of database predicates with respect to a set of ICs was introduced and used to capture the notion of possibly transitive relevance of a predicate for another, which is useful in consistent query answering. Here we can use similar graphs for each peer in relationship with its neighbors through a set of DECs, also taking into account the local ICs.…”

Section: A2 Query Sensitive Query Answeringmentioning

confidence: 99%

“…Several optimizations can be applied to solution programs (Caniupan and Bertossi 2010). An important one has to do with the materialization of the closed-worldassumption, which results through the rule 2.…”

Section: Proposition 61mentioning

confidence: 99%

“…Furthermore, there are mechanisms for computing consistent answers that avoid or minimize the physical generation of repairs. Logic programs for specifying database repairs as their stable models have been proposed and investigated in (Arenas et al 2003;Greco et al 2003;Caniupan and Bertossi 2010). Cf.…”

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confidence: 99%

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Consistency and trust in peer data exchange systems

Bertossi

Bravo

2016

Theory and Practice of Logic Programming

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We propose and investigate a semantics for peer data exchange systems where different peers are related by data exchange constraints and trust relationships. These two elements plus the data at the peers' sites and their local integrity constraints are made compatible via a semantics that characterizes sets of solution instances for the peers. They are the intended -possibly virtual-instances for a peer that are obtained through a data repair semantics that we introduce and investigate. The semantically correct answers from a peer to a query, the so-called peer consistent answers, are defined as those answers that are invariant under all its different solution instances. We show that solution instances can be specified as the models of logic programs with a stable model semantics. The repair semantics is based on null values as used in SQL databases, and is also of independent interest for repairs of single databases with respect to integrity constraints.

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