A Comprehensive XQuery to SQL Translation using Dynamic Interval Encoding

The W3C XQuery language recommendation, based on a hierarchical and ordered document model, supports a wide variety of constructs and use cases. There is a diversity of approaches and strategies for evaluating XQuery expressions, in many cases only dealing with limited subsets of the language. In this paper we describe an implementation approach that handles XQuery with arbitrarily-nested FLWR expressions, element constructors and built-in functions (including structural comparisons). Our proposal maps an XQuery expression to a single equivalent SQL query using a novel dynamic interval encoding of a collection of XML documents as relations, augmented with information tied to the query evaluation environment. The dynamic interval technique enables (suitably enhanced) relational engines to produce predictably good query plans that do not restrict the use of sort-merge join query operators. The benefits are realized despite the challenges presented by intermediate results that create arb...

• Type: Conference
• Year: 2003
• Where: SIGMOD
• Authors: David DeHaan, David Toman, Mariano P. Consens, M. Tamer Özsu
• Keywords: Database, Query Evaluation Environment, SIGMOD 2003, XQuery Expressions, XQuery Language Recommendation