The Community for Technology Leaders
RSS Icon
Subscribe
Issue No.03 - March (2009 vol.21)
pp: 401-414
E. Patrick Shironoshita , INFOTECH Soft, Inc., Miami
Yves R. Jean-Mary , INFOTECH Soft, Inc., Miami
Ray M. Bradley , INFOTECH Soft, Inc., Miami
Mansur R. Kabuka , INFOTECH Soft, Inc., Miami and University of Miami, Coral Gables
ABSTRACT
The SPARQL LeftJoin abstract operator is not distributive over Union; this limits the algebraic manipulation of graph patterns, which in turn restricts the ability to create query plans for distributed processing or query optimization. In this paper, we present semQA, an algebraic extension for the SPARQL query language for RDF, which overcomes this issue by transforming graph patterns through the use of an idempotent disjunction operator Or as a substitute for Union. This permits the application of a set of equivalences that transform a query into distinct forms. We further present an algorithm to derive the solution set of the original query from the solution set of a query where Union has been substituted by Or. We also analyze the combined complexity of SPARQL, proving it to be NP-complete. It is also shown that the SPARQL query language is not, in the general case, fixed-parameter tractable. Experimental results are presented to validate the query evaluation methodology presented in this paper against the SPARQL standard, to corroborate the complexity analysis, and to illustrate the gains in processing cost reduction that can be obtained through the application of semQA.
INDEX TERMS
Query processing, Query languages, Ontology
CITATION
E. Patrick Shironoshita, Yves R. Jean-Mary, Ray M. Bradley, Mansur R. Kabuka, "semQA: SPARQL with Idempotent Disjunction", IEEE Transactions on Knowledge & Data Engineering, vol.21, no. 3, pp. 401-414, March 2009, doi:10.1109/TKDE.2008.91
REFERENCES
[1] J. de Bruijn, S. Tessaris, and E. Franconi, “Logical Reconstruction of RDF and Ontology Languages,” Proc. Third Int'l Workshop Principles and Practice of Semantic Web Reasoning (PPSWR), 2005.
[2] E.F. Codd, “A Relational Model of Data for Large Shared Data Banks,” Comm. ACM, vol. 13, no. 6, pp. 377-387, 1970.
[3] R. Cyganiak, “A Relational Algebra for SPARQL,” HP Laboratories Bristol, http://www.hpl.hp.com/techreports/2005HPL-2005-170.pdf , 2005.
[4] R. Downey and M. Fellows, Parameterized Complexity. Springer, 1999.
[5] R. Downey, M. Fellows, and U. Taylor, “The Parameterized Complexity of Relational Database Queries and an Improved Characterization of W[1],” www.mcs.vuw.ac.nz/math/papersDMTCS_96.ps , 2008.
[6] J. Flum and M. Grohe, Parameterized Complexity Theory. Springer, 2006.
[7] F. Frasincar, G.-J. Houben, R. Vdovjak, and P. Barna, “RAL: An Algebra for Querying RDF,” World Wide Web, vol. 7, no. 1, pp. 83-109, 2004.
[8] M. Grohe, “Parameterized Complexity for the Database Theorist,” ACM SIGMOD Record, vol. 31, no. 4, pp. 86-96, 2002.
[9] X. Huang, J. Lai, and S. Jennings, “Maximum Common Subgraph: Some Upper Bound and Lower Bound Results,” BMC Bioinformatics, 7 (Suppl 4): S6, 2006.
[10] Y. Jean-Mary and M. Kabuka, “ASMOV: Ontology Alignment with Semantic Validation,” Proc. Joint Workshop Semantics, Ontologies, Databases (SWDB-ODBIS '07), 2007.
[11] F. Manola and E. Miller, RDF Primer, W3C recommendation, http://www.w3.org/TRrdf-primer/, Feb. 2004.
[12] C. Papadimitriou and M. Yannakakis, “On the Complexity of Database Queries,” J. Computer and System Sciences, vol. 58, no. 3, pp. 407-427, 1999.
[13] J. Pérez, M. Arenas, and C. Gutiérrez, “Semantics and Complexity of SPARQL,” Proc. Fifth Int'l Semantic Web Conf. (ISWC '06), http://arxiv.org/PS_cache/cs/pdf/06050605124v1.pdf , Nov. 2006.
[14] J. Pérez, M. Arenas, and C. Gutiérrez, “Semantics of SPARQL,” http://ing.utalca.cl/~jperez/paperssparql_semantics.pdf , 2008.
[15] A. Polleres, “SPARQL Rules!,” GIA technical report, Universidad Rey Juan Carlos, http://platon.escet.urjc.es/~axel/ publications GIA-TR-2006-11-28.pdf, Nov. 2006.
[16] E. Prud'hommeaux and A. Seaborne, SPARQL Query Language for RDF, W3C Recommendation [updated 2008 Jan. 15, accessed 2008 Feb. 20], http://www.w3.org/TRrdf-sparql-query/, 2008.
[17] E.P. Shironoshita, M.T. Ryan, and M.R. Kabuka, “Cardinality Estimation for the Optimization of Queries on Ontologies,” ACM SIGMOD Record, June 2007.
[18] M. Vardi, “The Complexity of Relational Query Languages,” Proc. 14th Ann. ACM Symp. Theory of Computing (STOC '82), pp. 137-146, 1982.
18 ms
(Ver 2.0)

Marketing Automation Platform Marketing Automation Tool