The State of Native XML databases

[Ken North]

Re:  The State of Native XML databases>> On the relational-XML 
database side, both Oracle 10g and Microsoft SQL Server 2005 support XML 
integration in the same manner as DB2 9, extending the relational model to 
include an XML type when defining column types for a table.

Oracle, Microsoft SQL Server and IBM DB2 support the XML type, but there are 
differences in the architecture and storage engine they use for XML. Supporting 
XML brought architectural changes when Oracle moved from 8i to 9i. Microsoft SQL 
Server 2008 adds a new HierarchyID system type for operating with 
tree-structured information. The DB2 architecture changed between versions 8 and 
9.

This DB2 magazine article explains DB2 version 9 changes for XML:
http://www.db2mag.com/story/showArticle.jhtml?articleID=191502768

>> W3C maintains a list of implementations : 
>> http://www.w3.org/XML/Query/#implementations

This site has lists of DB2 Extenders, drivers, data providers - and XQuery 
implementations:
http://www.SQLSummit.com/XQueryProv.htm