You routinely encounter hierarchies in organization charts,
parts lists, invoices that have line items, and the file system
on your computer. The advent of XML provided a convenient way to
represent these hierarchies by nesting entities (XML elements)
inside one another. This approach is convenient when you're
designing applications that present data hierarchically. But
inserting hierarchically formatted XML data into your SQL Server
database can pose a challenge, especially when the tables in
your database use IDENTITY columns for primary keys, making it
difficult to properly store the auto-generated key values in
related tables. Fortunately, OpenXML meta-properties provide a
solution for obtaining these key values and correlating them to
related entities in the XML.  OpenXML and @mp:id  With SQL
Server 2000, Microsoft released the OpenXML T-SQL keyword, which
lets you use T-SQL code to extract data from an XML document.
You can think of OpenXML as providing a relational view or
rowset (similar to the OPENRO