Abstract
The class of unions of conjunctive queries (UCQ) has been shown to be particularly well-behaved for data exchange; its certain answers can be computed in polynomial time (in terms of data complexity). However, this is not the only class with this property; the certain answers to any Datalog program can also can be computed in polynomial time. The problem is that both UCQ and Datalog do not allow for negated atoms, while most database query languages are equipped with negation. Unfortunately, adding an unrestricted form of negation to these languages yields to intractability of the problem of computing certain answers.
In order to face this challenge, we have recently proposed a language, called Datalog C( ≠ ) [5], that extends Datalog with a restricted form of negation while keeping the good properties of Datalog, and UCQ, for data exchange. In this article, we provide evidence in favor of the use of Datalog C( ≠ ) as a query language for data exchange systems. More precisely, we introduce the syntax and semantics of Datalog C( ≠ ), we present some of the fundamental results about this language shown in [5], and we extend those results to the case of data exchange settings that allow for constraints in the target schema. All of these results provide justification for the use of Datalog C( ≠ ) in practice.
This is a preview of subscription content, log in via an institution to check access.
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
Abiteboul, S., Duschka, O.: Answering queries using materialized views. Gemo report 383
Abiteboul, S., Hull, R., Vianu, V.: Foundations of databases. Addison-Wesley, Reading (1995)
Afrati, F.N., Li, C., Pavlaki, V.: Data exchange in the presence of arithmetic comparisons. In: EDBT, pp. 487–498 (2008)
Arenas, M., Barceló, P., Fagin, R., Libkin, L.: Locally consistent transformations and query answering in data exchange. In: PODS, pp. 229–240 (2004)
Arenas, M., Barceló, P., Reutter, J.: Query languages for data exchange: Beyond unions of conjunctive queries. Accepted for publication in Theory of Computing Systems, ToCS (2010); Preliminary version in Proceedings 12th International Conference on Database Theory (ICDT 2009), pp. 73–83 (2009)
Beeri, C., Vardi, M.Y.: A proof procedure for data dependencies. Journal of the ACM 31(4), 718–741 (1984)
Calì, A., Gottlob, G., Pieris, A.: Query answering under non-guarded rules in datalog+/-. In: Hitzler, P., Lukasiewicz, T. (eds.) RR 2010. LNCS, vol. 6333, pp. 1–17. Springer, Heidelberg (2010)
Deutsch, A., Nash, A., Remmel, J.B.: The chase revisited. In: PODS, pp. 149–158 (2008)
Fagin, R., Kolaitis, P., Popa, L., Tan, W.C.: Composing schema mappings: Second-order dependencies to the rescue. In: PODS, pp. 83–94 (2004)
Fagin, R., Kolaitis, P.G., Miller, R.J., Popa, L.: Data exchange: semantics and query answering. Theoretical Computer Science 336(1), 89–124 (2005)
Fagin, R., Kolaitis, P.G., Popa, L.: Data exchange: getting to the core. ACM Transactions on Database Systems 30(1), 174–210 (2005)
Kolaitis, P.: Schema mappings, data exchange, and metadata management. In: PODS, pp. 61–75 (2005)
Kolaitis, P., Panttaja, J., Tan, W.-C.: The complexity of data exchange. In: PODS, pp. 30–39 (2006)
Imielinski, T., Lipski, W.: Incomplete information in relational databases. Journal of the ACM 31, 761–791 (1984)
Lenzerini, M.: Data integration: A theoretical perspective. In: PODS, pp. 233–246 (2002)
Libkin, L.: Elements of Finite Model Theory. Springer, Heidelberg (2004)
Libkin, L.: Data exchange and incomplete information. In: PODS, pp. 60–69 (2006)
Libkin, L., Sirangelo, C.: Data exchange and schema mappings in open and closed worlds. In: PODS, pp. 139–148 (2008)
Ma̧dry, A.: Data exchange: On the complexity of answering queries with inequalities. Information Processing Letters 94(6), 253–257 (2005)
Vardi, M.Y.: The complexity of relational query languages. In: STOC, pp. 137–146 (1982)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2011 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Arenas, M., Barceló, P., Reutter, J. (2011). Datalog as a Query Language for Data Exchange Systems. In: de Moor, O., Gottlob, G., Furche, T., Sellers, A. (eds) Datalog Reloaded. Datalog 2.0 2010. Lecture Notes in Computer Science, vol 6702. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-24206-9_18
Download citation
DOI: https://doi.org/10.1007/978-3-642-24206-9_18
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-24205-2
Online ISBN: 978-3-642-24206-9
eBook Packages: Computer ScienceComputer Science (R0)