Transforming XPath Queries for Bottom-Up Query Processing

The widespreading of XML as a content-description language on the Web requires advanced processing and management techniques for huge XML databases. XPath is a standard language for extracting the specified elements from XML documents, and its efficient support is one of the key issues in the current XML database technology. In this paper, we propose an XPath query transformation method for the efficient query processing. It transforms top-down, navigation-based XPath queries into equivalent bottom-up query plans by using schema information. Based on this technique, we can achieve efficient set-oriented processing of XPath queries with the support of index mechanisms.