Abstract
In a data exchange setting with target constraints, it is often the case that a given source instance has no solutions. Intuitively, this happens when data sources contain inconsistent or conflicting information that is exposed by the target constraints at hand. In such cases, the semantics of target queries trivialize, because the certain answers of every target query over the given source instance evaluate to “true”. The aim of this paper is to introduce and explore a new framework that gives meaningful semantics in such cases by using the notion of exchange-repairs. Informally, an exchange-repair of a source instance is another source instance that differs minimally from the first, but has a solution. In turn, exchange-repairs give rise to a natural notion of exchange-repair certain answers (in short, XR-certain answers) for target queries in the context of data exchange with target constraints.
After exploring the structural properties of exchange-repairs, we focus on the problem of computing the XR-certain answers of conjunctive queries. We show that for schema mappings specified by source-to-target GAV dependencies and target equality-generating dependencies (egds), the XR-certain answers of a target conjunctive query can be rewritten as the consistent answers (in the sense of standard database repairs) of a union of source conjunctive queries over the source schema with respect to a set of egds over the source schema, thus making it possible to use a consistent query-answering system to compute XR-certain answers in data exchange. In contrast, we show that this type of rewriting is not possible for schema mappings specified by source-to-target LAV dependencies and target egds. We then examine the general case of schema mappings specified by source-to-target GLAV constraints, a weakly acyclic set of target tgds and a set of target egds. The main result asserts that, for such settings, the XR-certain answers of conjunctive queries can be rewritten as the certain answers of a union of conjunctive queries with respect to the stable models of a disjunctive logic program over a suitable expansion of the source schema.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Afrati, F.N., Kolaitis, P.G.: Repair checking in inconsistent databases: algorithms and complexity. In: Fagin, R. (ed.) ICDT. ACM International Conference Proceeding Series, vol. 361, pp. 31–41. ACM (2009)
Alviano, M., Faber, W., Leone, N., Perri, S., Pfeifer, G., Terracina, G.: The disjunctive datalog system dlv. In: Datalog, pp. 282–301 (2010)
Arenas, M., Barceló, P., Libkin, L., Murlak, F.: Relational and XML Data Exchange. Synthesis Lectures on Data Management. Morgan & Claypool Publishers (2010)
Arenas, M., Bertossi, L.E., Chomicki, J.: Consistent query answers in inconsistent databases. In: Vianu, V., Papadimitriou, C.H. (eds.) PODS, pp. 68–79. ACM Press (1999)
Bertossi, L.E.: Database Repairing and Consistent Query Answering. Synthesis Lectures on Data Management. Morgan & Claypool Publishers (2011)
Calì, A., Lembo, D., Rosati, R.: On the decidability and complexity of query answering over inconsistent and incomplete databases. In: Neven, F., Beeri, C., Milo, T. (eds.) PODS, pp. 260–271. ACM (2003)
Calì, A., Lembo, D., Rosati, R.: Query rewriting and answering under constraints in data integration systems. In: Gottlob, G., Walsh, T. (eds.) IJCAI, pp. 16–21. Morgan Kaufmann (2003)
ten Cate, B., Fontaine, G., Kolaitis, P.G.: On the data complexity of consistent query answering. In: Deutsch, A. (ed.) ICDT, pp. 22–33. ACM (2012)
Chomicki, J., Marcinkowski, J.: Minimal-change integrity maintenance using tuple deletions. Inf. Comput. 197(1-2), 90–121 (2005)
Duschka, O.M., Genesereth, M.R.: Answering recursive queries using views. In: Mendelzon, A.O., Özsoyoglu, Z.M. (eds.) PODS, pp. 109–116. ACM Press (1997)
Fagin, R., Kolaitis, P.G., Miller, R.J., Popa, L.: Data exchange: semantics and query answering. Theor. Comput. Sci. 336(1), 89–124 (2005)
Fuxman, A., Miller, R.J.: First-order query rewriting for inconsistent databases. J. Comput. Syst. Sci. 73(4), 610–635 (2007)
Gelfond, M., Lifschitz, V.: The stable model semantics for logic programming. In: Kowalski, R.A., Bowen, K.A. (eds.) ICLP/SLP, pp. 1070–1080. MIT Press (1988)
Grahne, G., Onet, A.: Data correspondence, exchange and repair. In: Segoufin, L. (ed.) ICDT. pp. 219–230. ACM International Conference Proceeding Series. ACM (2010)
Janhunen, T., Oikarinen, E.: Capturing parallel circumscription with disjunctive logic programs. In: Alferes, J.J., Leite, J. (eds.) JELIA 2004. LNCS (LNAI), vol. 3229, pp. 134–146. Springer, Heidelberg (2004)
Kolaitis, P.G., Panttaja, J., Tan, W.C.: The complexity of data exchange. In: Vansummeren, S. (ed.) PODS, pp. 30–39. ACM (2006)
Lenzerini, M.: Data integration: A theoretical perspective. In: Popa, L., Abiteboul, S., Kolaitis, P.G. (eds.) PODS, pp. 233–246. ACM (2002)
Leone, N., Pfeifer, G., Faber, W., Eiter, T., Gottlob, G., Perri, S., Scarcello, F.: The dlv system for knowledge representation and reasoning. ACM Trans. Comput. Log. 7(3), 499–562 (2006)
Marileo, M.C., Bertossi, L.E.: The consistency extractor system: Answer set programs for consistent query answering in databases. Data Knowl. Eng. 69(6), 545–572 (2010)
Marnette, B.: Generalized schema-mappings: from termination to tractability. In: Paredaens, J., Su, J. (eds.) PODS, pp. 13–22. ACM (2009)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2014 Springer International Publishing Switzerland
About this paper
Cite this paper
ten Cate, B., Halpert, R.L., Kolaitis, P.G. (2014). Exchange-Repairs: Managing Inconsistency in Data Exchange. In: Kontchakov, R., Mugnier, ML. (eds) Web Reasoning and Rule Systems. RR 2014. Lecture Notes in Computer Science, vol 8741. Springer, Cham. https://doi.org/10.1007/978-3-319-11113-1_10
Download citation
DOI: https://doi.org/10.1007/978-3-319-11113-1_10
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-11112-4
Online ISBN: 978-3-319-11113-1
eBook Packages: Computer ScienceComputer Science (R0)