The value() method is used to obtain a single value from the XML document data.
The XML native data type can be used since SQL Server 2005 to parse XML and produce a rowset replacing the use of the OPENXML rowset provider.
Transact-SQL supports a subset of the XQuery language that is used for querying the XML data type.
Description of how to generate XML instances and and XML is stored in the SQL Server.
SQL Server XQuery extension methods in order to bind the non-XML relational data inside XML.
Usefull Routines Sample Code
The modify() method allows to change the contents of the XML data stored in a XML column without having to retrieve it, modfy it, and put it back afterwards.
The nodes() method is used to obtain a single column rowset of nodes from the XML data.
The exist() method is used to test whether a specific node/value exists in the XML data.
The query() method is used to select non-typed XML fragment from the XML data.