(SQL Server) Compress XML Tree

Demonstrates how to compress and restore the entire subtree rooted at an XML node.

The input XML, available at http://www.chilkatsoft.com/data/compress2.xml, is this:

<root>
    <lazydog>
        <fox>The quick brown fox jumps over the lazy dog</fox>
    </lazydog>
    <fox>The quick brown fox jumps over the lazy dog</fox>
    <child>
        <grandchild>The quick brown fox jumps over the lazy dog</grandchild>
    </child>
    <child>
        <grandchild>The quick brown fox jumps over the lazy dog</grandchild>
    </child>
</root>

Download Chilkat XML ActiveX

CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @xml int
    EXEC @hr = sp_OACreate 'Chilkat.Xml', @xml OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @success int

    --  The sample input XML is available at http://www.chilkatsoft.com/data/compress2.xml
    EXEC sp_OAMethod @xml, 'LoadXmlFile', @success OUT, 'compress2.xml'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @xml, 'LastErrorText', @sTmp0 OUT

        PRINT @sTmp0
        RETURN
      END

    --  Zip compress the root node's entire subtree:
    EXEC sp_OAMethod @xml, 'ZipTree', NULL

    --  Examine the new XML document:
    EXEC sp_OAMethod @xml, 'GetXml', @sTmp0 OUT
    PRINT @sTmp0

    --  This is the XML w/ the compressed subtree in Base64 encoded format:
    --  
<root><![CDATA[4+WyKcrPL7Hj5VIAApucxKrKlPx0KBcslJZfYReSkapQWJqZnK2QVJRfnqcAFFPIKs0tKFbIL0st
UigBSoN0KgC12uiDNECN00c1jyKzkjMyc1KQHZZelJiXAhElyUwkfTBnovDoYZGNPjTUAQ==
]]></root>


    --  Now uncompress and show that the original subtree was restored:
    EXEC sp_OAMethod @xml, 'UnzipTree', NULL
    EXEC sp_OAMethod @xml, 'GetXml', @sTmp0 OUT
    PRINT @sTmp0


END
GO