Abstract
Increasing amount of RDF data on the Web drives the need for its efficient and effective management. In this light, numerous researchers have proposed to use RDBMSs to store and query RDF annotations using the SQL and SPARQL query languages. The first few attempts at SPARQL-to-SQL translation revealed non-trivial challenges related to correctness and efficiency of such translation in the presence of nested optional graph patterns. In this paper, we propose to extend relational databases with a novel relational operator, nested optional join (NOJ), that is more efficient than left outer join in processing nested optional graph patterns. We design three efficient algorithms to implement the new operator in relational databases: (1) nested-loops NOJ algorithm, NL-NOJ, (2) sort-merge NOJ algorithm, SM-NOJ, and (3) simple hash NOJ algorithm, SH-NOJ. Based on a real life RDF dataset, we demonstrate the efficiency of our algorithms by comparing them with the corresponding left outer join implementations.
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References
RDF Primer. W3C Recommendation (10 February 2004), http://www.w3.org/TR/rdf-primer/
RDFQL database command reference. http://www.intellidimension.com/pages/rdfgateway/reference/db/default.rsp
SPARQL Query Language for RDF. W3C Working Draft (4 October 2006), http://www.w3.org/TR/2006/WD-rdf-sparql-query-20061004/
User guide for Sesame. Updated for Sesame release 1.2.3. http://www.openrdf.org/doc/sesame/users/index.html
WordNet, a lexical database for the English language. http://wordnet.princeton.edu/
Berners-Lee, T., Hendler, J., Lassila, O.: The Semantic Web. Scientific American (May 2001)
Broekstra, J., Kampman, A., van Harmelen, F.: Sesame: A Generic Architecture for Storing and Querying RDF and RDF Schema. In: Horrocks, I., Hendler, J. (eds.) ISWC 2002. LNCS, vol. 2342, p. 54. Springer, Heidelberg (2002)
Chebotko, A., Atay, M., Lu, S., Fotouhi, F.: Extending relational databases with a nested optional join for efficient Semantic Web query processing. Technical Report TR-DB-112006-CALF (November 2006), http://www.cs.wayne.edu/~artem/main/research/TR-DB-112006-CALF.pdf
Chebotko, A., Lu, S., Jamil, H.M., Fotouhi, F.: Semantics preserving SPARQL-to-SQL query translation for optional graph patterns. Technical Report TR-DB-052006-CLJF (May 2006), http://www.cs.wayne.edu/~artem/main/research/TR-DB-052006-CLJF.pdf
Codd, E.F.: A relational model of data for large shared data banks. Commun. ACM 13(6), 377–387 (1970)
Codd, E.F.: Relational completeness of data base sublanguages. In: Rustin, R. (ed.) Database Systems, pp. 65–98. Prentice-Hall, Englewood Cliffs (1972), also IBM Research Report RJ 987.
Cyganiak, R.: A relational algebra for SPARQL. Technical Report HPL-2005-170 (2005), http://www.hpl.hp.com/techreports/2005/HPL-2005-170.html
Elmasri, R., Navathe, S.B.: Fundamentals of Database Systems. Addison-Wesley, Reading (2004)
Harris, S., Shadbolt, N.R.: SPARQL Query Processing with Conventional Relational Database Systems. In: Dean, M., Guo, Y., Jun, W., Kaschek, R., Krishnaswamy, S., Pan, Z., Sheng, Q.Z. (eds.) WISE-WS 2005. LNCS, vol. 3807, pp. 235–244. Springer, Heidelberg (2005)
Kifer, M., Bernstein, A., Lewis, P.M.: Database Systems: An Application Oriented Approach. Addison-Wesley, Reading (2006)
Kim, W.: A new way to compute the product and join of relations. In: SIGMOD, pp. 179–187 (1980)
Mishra, P., Eich, M.H.: Join processing in relational databases. ACM Computing Surveys 24(1), 63–113 (1992), doi:10.1145/128762.128764
Pan, Z., Heflin, J.: DLDB: Extending relational databases to support Semantic Web queries. In: PSSS (2003)
Prud’hommeaux, E.: Notes on Adding SPARQL to MySQL. http://www.w3.org/2005/05/22-SPARQL-MySQL/
Prud’hommeaux, E.: Optimal RDF Access to Relational Databases. http://www.w3.org/2004/04/30-RDF-RDB-access/
Volz, R., Oberle, D., Motik, B., Staab, S.: KAON SERVER -A Semantic Web Management System. In: WWW, Alternate Tracks - Practice and Experience (2003)
Wilkinson, K., Sayers, C., Kuno, H., Reynolds, D.: Efficient RDF storage and retrieval in Jena2. In: SWDB (2003)
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Chebotko, A., Atay, M., Lu, S., Fotouhi, F. (2007). Relational Nested Optional Join for Efficient Semantic Web Query Processing. In: Dong, G., Lin, X., Wang, W., Yang, Y., Yu, J.X. (eds) Advances in Data and Web Management. APWeb WAIM 2007 2007. Lecture Notes in Computer Science, vol 4505. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-72524-4_45
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DOI: https://doi.org/10.1007/978-3-540-72524-4_45
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