SQL/XML Hierarchical Query Performance Analysis in an XML-Enabled Database System

The increase utilization of XML structure for data representation, exchange, and integration has strengthened the need for an efficient storage and retrieval of XML data. Currently, there are two major streams of XML data repositories. The first stream is the Native XML database systems which are built solely to store and manipulate XML data, and equipped with the standard XML query language known as XPath and XQuery. The second stream is the XML-Enabled database systems which are generally existing traditional database systems enhanced with XML storage capabilities. The SQL/XML standard for XML querying is used in these enabled database systems stream. The main specific characteristic of this standard is the fact that XPath and XQuery are embedded within SQL statements. To date, most existing work in XML query analysis have been focussing on the first stream of Native XML database systems. The focus of this paper is to present a taxonomy of different hierarchical query patterns in XML-Enabled database environment, and to analyze the performance of the different query structures using the SQL/XML standard.