Abstract
In ontology-based data access, an extensional database is enhanced by an ontology that generates new intensional knowledge which has to be considered when answering queries. In this setting, tractable data complexity (i.e., complexity w.r.t. the data only) of query answering is crucial, given the need to deal with large data sets. A well-known class of tractable ontology languages is the DL-lite family; however, in DL-lite it is impossible to express simple and useful integrity constraints that involve joins. To overcome this limitation, the Datalog+/- class of decidable languages uses tuple-generating dependencies (TGDs) as rules, thus allowing for conjunctions of atoms in the rule bodies, with suitable limitations to ensure decidability. In particular, sticky sets of TGDs allow for joins and variable repetition in rule bodies under certain conditions. In this paper we extend the notion of stickiness by introducing weakly-sticky sets of TGDs, which also generalize the well-known weakly-acyclic sets of TGDs. We investigate the complexity of query answering under such language, and in addition we provide novel complexity results on weakly-acyclic sets of TGDs. Moreover, we present the novel class of sticky-join sets of TGDs, which generalizes both sticky sets of TGDs and so-called linear TGDs, an extension of inclusion dependencies.
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., Hull, R., Vianu, V.: Foundations of Databases. Addison-Wesley, Reading
Baget, J.-F., Leclère, M., Mugnier, M.-L., Salvat, E.: Extending decidable cases for rules with existential variables. In: Proc. of IJCAI, pp. 677–682 (2009)
Beeri, C., Vardi, M.Y.: The implication problem for data dependencies. In: Proc. of ICALP, pp. 73–85 (1981)
Cabibbo, L.: The expressive power of stratified logic programs with value invention. Inf. Comput. 147(1), 22–56 (1998)
Calì, A., Gottlob, G., Kifer, M.: Taming the infinite chase: Query answering under expressive relational constraints. In: Proc. of KR, pp. 70–80 (2008)
Calì, A., Gottlob, G., Lukasiewicz, T.: Datalog± A unified approach to ontologies and integrity constraints. In: Proc. of ICDT, pp. 14–30 (2009)
Calì, A., Gottlob, G., Lukasiewicz, T.: A general datalog-based framework for tractable query answering over ontologies. In: Proc. of PODS, pp. 77–86 (2009)
Calì, A., Gottlob, G., Pieris, A.: Advanced processing for ontological queries. In: Proc. of VLDB (to appear, 2010)
Calì, A., Gottlob, G., Pieris, A.: Advanced processing for ontological queries (2010), http://benner.dbai.tuwien.ac.at/staff/gottlob/CGP.pdf
Calì, A., Gottlob, G., Pieris, A.: Ontological reasoning with F-Logic Lite and its extensions. In: Proc. of AAAI (to appear, 2010)
Calì, A., Lembo, D., Rosati, R.: On the decidability and complexity of query answering over inconsistent and incomplete databases. In: Proc. of PODS, pp. 260–271 (2003)
Calvanese, D., De Giacomo, G., Lembo, D., Lenzerini, M., Rosati, R.: Tractable reasoning and efficient query answering in description logics: The DL-lite family. J. Autom. Reasoning 39(3), 385–429 (2007)
Dantsin, E., Eiter, T., Georg, G., Voronkov, A.: Complexity and expressive power of logic programming. ACM Comput. Surv. 33(3), 374–425 (2001)
Deutsch, A., Nash, A., Remmel, J.B.: The chase revisisted. In: Proc. of PODS, pp. 149–158 (2008)
Deutsch, A., Tannen, V.: Reformulation of XML queries and constraints. In: Proc. of ICDT, pp. 225–241 (2003)
Fagin, R., Kolaitis, P.G., Miller, R.J., Popa, L.: Data exchange: Semantics and query answering. Theor. Comput. Sci. 336(1), 89–124 (2005)
Johnson, D.S., Klug, A.C.: Testing containment of conjunctive queries under functional and inclusion dependencies. J. Comput. Syst. Sci. 28(1), 167–189 (1984)
Kolaitis, P.G., Panttaja, J.: Personal Communication (2009)
Kolaitis, P.G., Panttaja, J., Tan, W.-C.: The complexity of data exchange. In: Proc. of PODS, pp. 30–39 (2006)
Maier, D., Mendelzon, A.O., Sagiv, Y.: Testing implications of data dependencies. ACM Trans. Database Syst. 4(4), 455–469 (1979)
Mailharrow, D.: A classification and constraint-based framework for configuration. Artif. Intell. for Engineering Design, Analysis and Manufacturing 12(4), 383–397 (1998)
Panttaya, J.: Complexity in databases, games, and logics. PhD thesis, University of California Santa Cruz (2006)
Patel-Schneider, P.F., Horrocks, I.: A comparison of two modelling paradigms in the semantic web. J. Web Semantics 5(4), 240–250 (2007)
Poggi, A., Lembo, D., Calvanese, D., De Giacomo, G., Lenzerini, M., Rosati, R.: Linking data to ontologies. J. Data Semantics 10, 133–173 (2008)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2010 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Calì, A., Gottlob, G., Pieris, A. (2010). Query Answering under Non-guarded Rules in Datalog+/- . In: Hitzler, P., Lukasiewicz, T. (eds) Web Reasoning and Rule Systems. RR 2010. Lecture Notes in Computer Science, vol 6333. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-15918-3_1
Download citation
DOI: https://doi.org/10.1007/978-3-642-15918-3_1
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-15917-6
Online ISBN: 978-3-642-15918-3
eBook Packages: Computer ScienceComputer Science (R0)