Is it possible to create an indexed view from Xml Data in Sql Server 2008?

Question

I see from the 2005 documentation that you cannot create an indexed view from an Xml column.

Is this possible in 2008 or 2008R2? I can\'t find any documentation saying t

Answer 1

Depending on your need, what you could do is this:

• create a set of stored functions that extract certain bits of key information from your XML (function receives XML as input, extracts the info using XPath/XQuery, returns a VARCHAR or INT or something value)

  CREATE FUNCTION dbo.SomeFunction(@Input XML)
  RETURNS VARCHAR(20)
  WITH SCHEMABINDING
  AS BEGIN
     ......
  END
  

• add those key bits to your base table as computed columns that reference those functions, with the PERSISTED keyword:

  ALTER TABLE dbo.YourTable
     ADD ComputedColumns1 AS dbo.SomeFunction(XmlColumn) PERSISTED
  

• create your view on the table and those computed columns, with schemabinding:

  CREATE VIEW vYourView 
  WITH SCHEMABINDING
  AS  
        SELECT (list of columns)
        FROM dbo.YourTable
  

• create a unique, clustered index on that view - unless you've violated any of the requirements of the indexed view, this should work just fine:

  CREATE UNIQUE CLUSTERED INDEX CIX_YourView ON dbo.vYourView(.....)
  

This works fine if you need to extract a small number of key bits of information from an XML column - it's definitely not recommended for lots of XML elements / values.