How do I update XML parameters in this situation...?

Question

I have a table called Users that has an XML column, xmlSettings, that I store various data about the user's last session.  Here is a snippet of a typical xmlSettings doc:
<Forms>
   <Form name="InvoiceList">
      <Grid name="dbgInvoices">
        <GridLayout>
          <Columns>
            <Column key="field1" />
            <Column key="TableName.ID"/>
            <Column key="field2" />
            <Column key="TableName.SomeOtherField" />
            <Column key="field3" />
          </Columns>
        </GridLayout>
      </Grid>
   </Form>
   <Form name="SomeOtherForm">...</Form>
<Forms
Now in this document, there will be settings for many forms.  I need to change "TableName" to "SomeTable".  I need to go through all the forms of the <Forms> node, and for the node that has name=InvoiceList, I need to go
into the <Columns> nodes and change any mention of "TableName" to "SomeTable".  I only have to do this for the InvoiceList form.  Also, there will be a row in this table for each user, and each row has its own xmlSettings
column that will contain settings for many forms.  I need to do this for all rows in the table.  I'm assuming I need to use .nodes() somehow, but I can't quite figure it out.
I can probably do this with a sproc of some sort, but I'm guessing there's a query that will do it.

Answer 1

Saurabh
Your approach is correct but suggestion wont give the exact output what poster is looking at
The reason is since the update happens inside loop it will replace all the instances of key with your first replace value itself and will exit loop.
See the output for your illustration
<Forms>
<Form name="InvoiceList">
<Grid name="dbgInvoices">
<GridLayout>
<Columns>
<Column key="field1" />
<Column key="TableName.ID" />
<Column key="field2" />
<Column key="TableName.SomeOtherField" />
<Column key="field3" />
</Columns>
</GridLayout>
</Grid>
</Form>
<Form name="SomeOtherForm">...</Form>
</Forms>
The above xml would get replaced as
<Forms>
<Form name="InvoiceList">
<Grid name="dbgInvoices">
<GridLayout>
<Columns>
<Column key="field1" />
<Column key="SomeTable.ID" />
<Column key="field2" />
<Column key="SomeTable.ID" />
<Column key="field3" />
</Columns>
</GridLayout>
</Grid>
</Form>
<Form name="SomeOtherForm">...</Form>
</Forms>
If you see part in bold you can find that it will end up replacing all occurances with first key_val value from @table1
So the solution would be to do something like below
DECLARE @UserTable TABLE
userId INT IDENTITY(1, 1) ,
sUserName NVARCHAR(150) ,
xmlSettings XML
INSERT INTO @usertable
SELECT 'saurabh' ,
'<Forms>
<Form name="InvoiceList">
<Grid name="dbgInvoices">
<GridLayout>
<Columns>
<Column key="field1" />
<Column key="TableName.ID"/>
<Column key="field2" />
<Column key="TableName.SomeOtherField" />
<Column key="field3" />
<Column key="TableName.SomeOtherField2" />
<Column key="field3" />
</Columns>
</GridLayout>
</Grid>
</Form>
<Form name="SomeOtherForm">...</Form>
</Forms>'
UNION ALL
SELECT 'test' ,
'<Forms>
<Form name="InvoiceList">
<Grid name="dbgInvoices">
<GridLayout>
<Columns>
<Column key="field1" />
<Column key="TableName.ID"/>
<Column key="field2" />
<Column key="TableName.SomeOtherField" />
<Column key="field3" />
<Column key="TableName.SomeOtherField3" />
<Column key="field3" />
</Columns>
</GridLayout>
</Grid>
</Form>
<Form name="SomeOtherForm">...</Form>
</Forms>'
SELECT *
FROM @usertable
WHILE EXISTS ( SELECT 1
FROM @UserTable
WHERE xmlSettings.exist('//Grid[@name="dbgInvoices"]/GridLayout/Columns/Column[ contains(@key , "TableName")]') = 1 )
BEGIN
UPDATE m
SET xmlSettings.modify('replace value of (//Grid[@name="dbgInvoices"]/GridLayout/Columns/Column[ contains(@key , "TableName")]/@key)[1] with sql:column("replaceval") ')
FROM
(SELECT xmlSettings,REPLACE(t.u.value('./@key[1]','varchar(100)'),'TableName.','SomeOthertable.') AS replaceval
FROM @UserTable p
CROSS APPLY p.xmlSettings.nodes('/Forms/Form/Grid[@name="dbgInvoices"]/GridLayout/Columns/Column[ contains(@key , "TableName")]')t(u)
)m
END
SELECT *
FROM @usertable
Now check the output and you will see it will do replacement correctly
<Forms>
<Form name="InvoiceList">
<Grid name="dbgInvoices">
<GridLayout>
<Columns>
<Column key="field1" />
<Column key="SomeOthertable.ID" />
<Column key="field2" />
<Column key="SomeOthertable.SomeOtherField" />
<Column key="field3" />
<Column key="SomeOthertable.SomeOtherField2" />
<Column key="field3" />
</Columns>
</GridLayout>
</Grid>
</Form>
<Form name="SomeOtherForm">...</Form>
</Forms>
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