(SQL Server) Removing / Deleting Child Nodes from XML

Demonstrates various methods for removing child nodes from an XML document.

The input XML, available at http://www.chilkatsoft.com/data/fruit.xml, is this:

<root>
    <fruit color="red">apple</fruit>
    <fruit color="green">pear</fruit>
    <veg color="orange">carrot</veg>
    <meat animal="cow">beef</meat>
    <xyz>
        <fruit color="blue">blueberry</fruit>
        <veg color="green">broccoli</veg>
    </xyz>
    <fruit color="purple">grape</fruit>
    <cheese color="yellow">cheddar</cheese>
</root>

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @xml int
    -- Use "Chilkat_9_5_0.Xml" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Xml', @xml OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @xyz int

    DECLARE @success int

    -- The sample input XML is available at http://www.chilkatsoft.com/data/fruit.xml
    EXEC sp_OAMethod @xml, 'LoadXmlFile', @success OUT, 'fruit.xml'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @xml, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @xml
        RETURN
      END

    -- The RemoveChild method removes (discards) all direct
    -- children having the specified tag:
    EXEC sp_OAMethod @xml, 'RemoveChild', NULL, 'fruit'

    -- Show the resulting XML:

    PRINT 'Result with all direct children having a tag equal to "fruit" removed:'
    EXEC sp_OAMethod @xml, 'GetXml', @sTmp0 OUT
    PRINT @sTmp0

    -- The XML with the "fruit" direct children removed is shown below:
    -- Notice that the "fruit" node beneath "xyz" was not removed.
    -- This correct because it was not a direct child of the calling node.

    -- <root>
    --     <veg color="orange">carrot</veg>
    --     <meat animal="cow">beef</meat>
    --     <xyz>
    --         <fruit color="blue">blueberry</fruit>
    --         <veg color="green">broccoli</veg>
    --     </xyz>
    --     <cheese color="yellow">cheddar</cheese>
    -- </root>

    -- --------------------------------------------------------------------------
    -- Restore the original XML:
    EXEC sp_OAMethod @xml, 'LoadXmlFile', @success OUT, 'fruit.xml'

    -- The RemoveChildWithContent method removes the child
    -- having the exact content specified, regardless of the tag.  
    -- For example:
    EXEC sp_OAMethod @xml, 'RemoveChildWithContent', NULL, 'pear'

    -- Show the resulting XML:

    PRINT 'Result with the node containing "pear" removed:'
    EXEC sp_OAMethod @xml, 'GetXml', @sTmp0 OUT
    PRINT @sTmp0

    -- --------------------------------------------------------------------------
    -- Restore the original XML:
    EXEC sp_OAMethod @xml, 'LoadXmlFile', @success OUT, 'fruit.xml'

    -- The RemoveChildByIndex method removes the Nth direct
    -- child.  Indexing begins at 0.  The "xyz" child is at index 4:
    EXEC sp_OAMethod @xml, 'RemoveChildByIndex', NULL, 4

    -- Show the resulting XML:
    -- Notice that the entire "xyz" subtree is removed.

    PRINT 'Result with the node at index 4 removed:'
    EXEC sp_OAMethod @xml, 'GetXml', @sTmp0 OUT
    PRINT @sTmp0

    -- --------------------------------------------------------------------------
    -- Restore the original XML:
    EXEC sp_OAMethod @xml, 'LoadXmlFile', @success OUT, 'fruit.xml'

    -- Navigate to the node with tag "xyz"
    EXEC sp_OAMethod @xml, 'FindChild', @xyz OUT, 'xyz'

    -- Remove the "xyz" subtree making it it's own XML document
    -- with the "xyz" node at the root:
    EXEC sp_OAMethod @xyz, 'RemoveFromTree', NULL

    -- Show both XML documents:
    EXEC sp_OAMethod @xyz, 'GetXml', @sTmp0 OUT
    PRINT @sTmp0
    EXEC sp_OAMethod @xml, 'GetXml', @sTmp0 OUT
    PRINT @sTmp0

    -- Also, the TreeId property is an integer value assigned
    -- to nodes in an XML document.  All nodes belonging to
    -- the same XML document will have the same TreeId.
    -- Notice that the "xyz" node now has a different TreeId:

    EXEC sp_OAGetProperty @xyz, 'TreeId', @iTmp0 OUT
    PRINT 'xyz TreeId = ' + @iTmp0

    EXEC sp_OAGetProperty @xml, 'TreeId', @iTmp0 OUT
    PRINT 'xml TreeId = ' + @iTmp0

    EXEC @hr = sp_OADestroy @xyz


    EXEC @hr = sp_OADestroy @xml


END
GO