Abstract
The Web of Linked Data forms a single, globally distributed dataspace. Due to the openness of this dataspace, it is not possible to know in advance all data sources that might be relevant for query answering. This openness poses a new challenge that is not addressed by traditional research on federated query processing. In this paper we present an approach to execute SPARQL queries over the Web of Linked Data. The main idea of our approach is to discover data that might be relevant for answering a query during the query execution itself. This discovery is driven by following RDF links between data sources based on URIs in the query and in partial results. The URIs are resolved over the HTTP protocol into RDF data which is continuously added to the queried dataset. This paper describes concepts and algorithms to implement our approach using an iterator-based pipeline. We introduce a formalization of the pipelining approach and show that classical iterators may cause blocking due to the latency of HTTP requests. To avoid blocking, we propose an extension of the iterator paradigm. The evaluation of our approach shows its strengths as well as the still existing challenges.
Chapter PDF
Similar content being viewed by others
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
References
Berners-Lee, T.: Design Issues: Linked Data. (retrieved May 25, 2009), http://www.w3.org/DesignIssues/LinkedData.html
Bizer, C., Heath, T., Berners-Lee, T.: Linked data - the story so far. Journal on Semantic Web and Information Systems (in press, 2009)
Franklin, M.J., Halevy, A.Y., Maier, D.: From databases to dataspaces: A new abstraction for information management. SIGMOD Record 34(4), 27–33 (2005)
Prud’hommeaux, E., Seaborne, A.: SPARQL query language for RDF. W3C Recommendation (January 2008), http://www.w3.org/TR/rdf-sparql-query/ (retrieved June 11, 2009)
Sheth, A.P., Larson, J.A.: Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys 22(3), 183–236 (1990)
Garcia-Molina, H., Widom, J., Ullman, J.D.: Database Systems: The Complete Book. Prentice-Hall, Inc., Upper Saddle River (2002)
Graefe, G.: Query evaluation techniques for large databases. ACM Computing Surveys 25(2), 73–169 (1993)
Pirahesh, H., Mohan, C., Cheng, J., Liu, T.S., Selinger, P.: Parallelism in relational data base systems: Architectural issues and design approaches. In: Proceedings of the 2nd International Symposium on Databases in Parallel and Distributed Systems (DPDS), pp. 4–29. ACM, New York (1990)
Hartig, O., Mühleisen, H., Freytag, J.-C.: Linked data for building a map of researchers. In: Proceedings of 5th Workshop on Scripting and Development for the Semantic Web (SFSW) at ESWC (June 2009)
Bizer, C., Schultz, A.: Benchmarking the performance of storage systems that expose SPARQL endpoints. In: Proceedings of the Workshop on Scalable Semantic Web Knowledge Base Systems at ISWC (October 2008)
Quilitz, B., Leser, U.: Querying distributed RDF data sources with SPARQL. In: Bechhofer, S., Hauswirth, M., Hoffmann, J., Koubarakis, M. (eds.) ESWC 2008. LNCS, vol. 5021, pp. 524–538. Springer, Heidelberg (2008)
Langegger, A., Wöß, W., Blöchl, M.: A semantic web middleware for virtual data integration on the web. In: Bechhofer, S., Hauswirth, M., Hoffmann, J., Koubarakis, M. (eds.) ESWC 2008. LNCS, vol. 5021, pp. 493–507. Springer, Heidelberg (2008)
Oren, E., Delbru, R., Catasta, M., Cyganiak, R., Stenzhorn, H., Tummarello, G.: Sindice.com: A document-oriented lookup index for open linked data. International Journal of Metadata, Semantics and Ontologies 3(1) (2008)
Ding, L., Finin, T.W., Joshi, A., Pan, R., Cost, R.S., Peng, Y., Reddivari, P., Doshi, V., Sachs, J.: Swoogle: A search and metadata engine for the semantic web. In: Proceedings of the 13th ACM Conference on Information and Knowledge Management (CIKM), November 2004, pp. 652–659. ACM, New York (2004)
d’Aquin, M., Motta, E., Sabou, M., Angeletou, S., Gridinoc, L., Lopez, V., Guidi, D.: Toward a new generation of semantic web applications. IEEE Intelligent Systems 23(3), 20–28 (2008)
Berners-Lee, T., Chen, Y., Chilton, L., Connolly, D., Dhanaraj, R., Hollenbach, J., Lerer, A., Sheets, D.: Tabulator: Exploring and analyzing linked data on the semantic web. In: Proceedings of the 3rd Semantic Web User Interaction Workshop (SWUI) at ISWC (November 2006)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2009 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Hartig, O., Bizer, C., Freytag, JC. (2009). Executing SPARQL Queries over the Web of Linked Data. In: Bernstein, A., et al. The Semantic Web - ISWC 2009. ISWC 2009. Lecture Notes in Computer Science, vol 5823. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-04930-9_19
Download citation
DOI: https://doi.org/10.1007/978-3-642-04930-9_19
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-04929-3
Online ISBN: 978-3-642-04930-9
eBook Packages: Computer ScienceComputer Science (R0)