Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

If, for example, we wanted to increase the original 1.5 labor hours in our .value example, we might
write something like:
WITH XMLNAMESPACES (‘http://schemas.microsoft.com/sqlserver/2004/07/
adventure-works/ProductModelManuInstructions’ AS PI)
UPDATE Production.ProductModel
SET Instructions.modify(‘replace value of (/PI:root/PI:Location/@LaborHours)[1]
with 1.75’)
WHERE ProductModelID = 66;
Note that the URL portion of the namespace declaration must be entered on a single line. They are
shown here word wrapped onto multiple lines because there is a limit to the number of characters we
can show per line in print. Make sure you include the entire URL on a single line.
Now if we re-run our .value command:
WITH XMLNAMESPACES
(‘http://schemas.microsoft.com/sqlserver/2004/07/adventure-works/ProductModelManuIn
structions’ AS PI)
SELECT ProductModelID, Instructions.value(‘(/PI:root/PI:Location/@LaborHours)[1]’,
‘decimal (5,2)’) AS Location
FROM Production.ProductModel
WHERE ProductModelID = 66;
Note that the URL portion of the namespace declaration must be entered on a single line. They are
shown here word wrapped onto multiple lines because there is a limit to the number of characters we
can show per line in print. Make sure you include the entire URL on a single line.
We get a new value:
.nodes
ProductModelID Location
-------------- ---------------------------------------
66 1.75
(1 row(s) affected)
Chapter 16: A Brief XML Primer
Note the way that this is essentially an UPDATE within an UPDATE. We are modifying the SQL Server
row, so we must use an UPDATE statement to tell SQL Server that our row of relational data (which just
happens to have XML within it) is to be updated. We must also use the replace value of keyword
to specify the XML portion of the update.
.nodes is used to take blocks of XML and separate what would have, were it stored in a relational form,
been multiple rows of data. Taking one XML document and breaking it into individual parts in this way
is referred to as shredding the document.
What we are doing with .nodes is essentially breaking the instances of XML data into their own table
(with as many rows as there are instances of data meeting that XQuery criteria). As you might expect,
this means we need to treat .nodes results as a table rather than as a column. The primary difference
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