"In the early days of XML, imperative programming (navigation through the XML DOM) was all the rage. The XQuery language in general and XQuery inside the database in particular make it possible for the query engine writers to approach the task of optimizing queries against XML. The chances of success are good because these folks have 20 years or so of practical experience optimizing SQL queries against the relational data model. The SQL Server 2005 implementation of XQuery over the built-in XML data type holds the same promise of a declarative language, with optimization through a query engine. And the query engine that SQL Server 2005 XQuery uses is the one built-in to SQL Server. SQL Server 2005 XQuery uses the relational engine, with XQuery-specific enhancements. As an example, XQuery mandates that the results be returned in document order, even if you don't use "order by" in the query."
Monday, October 3, 2005 11:56 PM