Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
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SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
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ACM Transactions on Database Systems (TODS)
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Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Rainbow: mapping-driven XQuery processing system
Proceedings of the 2002 ACM SIGMOD international conference on Management of data
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Proceedings of the eleventh international conference on Information and knowledge management
ICDE '96 Proceedings of the Twelfth International Conference on Data Engineering
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Proceedings of the 27th International Conference on Very Large Data Bases
EDBT '02 Proceedings of the Worshops XMLDM, MDDE, and YRWS on XML-Based Data Management and Multimedia Engineering-Revised Papers
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IDEAS '02 Proceedings of the 2002 International Symposium on Database Engineering & Applications
Nested Queries in Object Bases
DBLP-4 Proceedings of the Fourth International Workshop on Database Programming Languages - Object Models and Languages
Rainbow: multi-XQuery optimization using materialized XML views
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
Nested Queries and Quantifiers in an Ordered Context
ICDE '04 Proceedings of the 20th International Conference on Data Engineering
Efficient algorithms for processing XPath queries
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
XMark: a benchmark for XML data management
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
A framework for using materialized XPath views in XML query processing
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
On testing satisfiability of tree pattern queries
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
Containment of nested XML queries
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
Let SQL drive the XQuery workhorse (XQuery join graph isolation)
Proceedings of the 13th International Conference on Extending Database Technology
A dataflow graph transformation language and query rewriting system for RDF ontologies
SSDBM'12 Proceedings of the 24th international conference on Scientific and Statistical Database Management
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XQuery, the defacto XML query language, is a functional language with operational semantics, which precludes the direct application of classical query optimization techniques. The features of XQuery, such as nested expressions and ordered semantics, further aggravate this situation. The appropriate extension of existing optimization techniques to XQuery processing hence represents an important and non-trivial task. We propose an algebraic rewriting technique of nested XQuery expressions containing explicit orderby clauses. Unlike prior work, this technique enables the optimization of nested XQuery expressions not only with set but also with ordered sequence semantics. Our technique is based on two steps. First, we perform order-sensitive algebraic query unnesting. Second, we apply query minimization techniques that exploit pairwise XPath set containment after pulling up order-sensitive operations. We illustrate how our proposed technique is able to not only successfully tackle the XQuery logical optimization problem solved in the NEXT framework, but also to correctly support ordered semantics. We have implemented the proposed optimization techniques on top of the XAT algebraic framework in our RainbowCore project. We show the performance gain achievable by our approach using an experimental study with the RainbowCore engine.