R-Programs: A Framework for Distributing XML Structural Joins across Function Calls
Structural joins and, in particular, twig joins are essential operations in XML query processing. Algorithms presented so far treat a twig join as a single operator with multiple inputs. However, in XQuery and XSLT, a twig pattern may be scattered across several functions (templates); thus, function integration is required before the application of a twig join operator. This paper presents R-programs – a novel evaluation framework based on an expanding network of operators. In this environment, a function may repeatedly and bidirectionally interact with its caller; consequently, a structural join algorithm may be distributed across the boundary of a function. Given this ability, function integration is no longer required and twig join algorithms become applicable even in the presence of recursive functions.
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- 1.Grust, T., Rittinger, J.: Jump through Hoops to Grok the Loops Pathfinder’s Purely Relational Account of XQuery-Style Iteration Semantics. In: Proceedings of the ACM SIGMOD/PODS 5th International Workshop on XQuery Implementation, Experience and Perspectives, XIME-P 2008 (2008)Google Scholar
- 2.Grust, T., Mayr, M., Rittinger, J.: XQuery Join Graph Isolation: Celebrating 30+ Years of XQuery Processing Technology. In: ICDE 2009, Proceedings of the 2009 IEEE International Conference on Data Engineering, Washington, DC, USA, pp. 1167–1170. IEEE Computer Society, Los Alamitos (2009)Google Scholar
- 5.Che, D.: Holistically Processing XML Twig Queries with AND, OR, and NOT Predicates. In: InfoScale 2007, Proceedings of the 2nd International Conference on Scalable Information Systems, ICST, Brussels, Belgium, pp. 1–4. ICST (Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering) (2007)Google Scholar
- 7.Bednárek, D.: Bulk Evaluation of User-Defined Functions in XQuery. PhD Thesis, Department of Software Engineering, Charles University, Prague, the Czech Republic (2009)Google Scholar
- 12.Bača, R., Krátký, M., Snášel, V.: On the Efficient Search of an XML Twig Query in Large DataGuide Trees. In: IDEAS 2008, Proceedings of the 2008 International Symposium on Database Engineering and Applications, pp. 149–158. ACM, New York (2008)Google Scholar