XML in SQL Server 2008
September 24, 2008
This is a follow-up to my look at XML in SQL Server 2005.
With the recent release of SQL Server 2008, Microsoft made updates to the XML support in SQL Server. In particular, they made improvements to the XML Schema Definitions (XSD) that they support, they added support for the
let clause in XQuery FLWOR expressions, and they added support for certain XML data manipulation insertions.
It is good to see support for the XQuery
let clause, although I actually removed a reference to their lack of support for the
let clause from my previous post because I felt that it was not a big deal. The expanded XML schema and XML manipulation support will prove useful for users. However, as far as I know (and I am relying on the Microsoft documentation here), the primary issues remain:
- SQL Server does not allow multiple versions of a schema in the same schema collection.
- SQL Server does not support indexing individual elements and attributes.
- The SQL/XML implementation includes non-standard extensions.
- SQL Server does not support standalone XQuery.
And you still need to carefully evaluate the performance of the following for your environment:
- Queries based on path expressions.
- Queries against large XML documents.
- Creating and updating indexes.
The following sources were consulted when compiling this post:
- What’s New for XML in SQL Server 2008, SQL Server Technical Article, August 2008.