SQL Server

Iterate over Direct Child Nodes by Index

See more XML Examples

Demonstrates some ways to iterate over direct child nodes by index.

The input XML, available at http://www.chilkatsoft.com/data/get_child.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>

SQL Server

-- 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 @sTmp1 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    DECLARE @xml int
    EXEC @hr = sp_OACreate 'Chilkat.Xml', @xml OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @child int

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

    -- The NumChildren property contains the number of direct
    -- child nodes.  Note: The child nodes under "xyz" are NOT
    -- direct children of "root".  Therefore, the "root" node has
    -- 7 direct children

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

    -- Iterate over the direct children by index. The first child
    -- is at index 0.
    DECLARE @i int

    EXEC sp_OAGetProperty @xml, 'NumChildren', @iTmp0 OUT
    SELECT @i = 0
    WHILE @i <= @iTmp0 - 1
      BEGIN
        --  access the tag and content directly by index:

        EXEC sp_OAMethod @xml, 'GetChildTagByIndex', @sTmp0 OUT, @i

        EXEC sp_OAMethod @xml, 'GetChildContentByIndex', @sTmp1 OUT, @i
        PRINT @i + ': ' + @sTmp0 + ' : ' + @sTmp1

        SELECT @i = @i + 1
      END

    PRINT '-----'

    -- Do the same as the above loop, but get the child node
    -- and access the Tag and Content properties:
    EXEC sp_OAGetProperty @xml, 'NumChildren', @iTmp0 OUT
    SELECT @i = 0
    WHILE @i <= @iTmp0 - 1
      BEGIN
        EXEC sp_OAMethod @xml, 'GetChild', @child OUT, @i

        EXEC sp_OAGetProperty @child, 'Tag', @sTmp0 OUT

        EXEC sp_OAGetProperty @child, 'Content', @sTmp1 OUT
        PRINT @i + ': ' + @sTmp0 + ' : ' + @sTmp1
        EXEC @hr = sp_OADestroy @child

        SELECT @i = @i + 1
      END

    PRINT '-----'

    -- Do the same as the above loop, but instead of creating
    -- a new object instance for each child, call GetChild2 to
    -- update the object's reference instead.
    EXEC sp_OAGetProperty @xml, 'NumChildren', @iTmp0 OUT
    SELECT @i = 0
    WHILE @i <= @iTmp0 - 1
      BEGIN
        -- Navigate to the Nth child.  
        EXEC sp_OAMethod @xml, 'GetChild2', @success OUT, @i

        EXEC sp_OAGetProperty @xml, 'Tag', @sTmp0 OUT

        EXEC sp_OAGetProperty @xml, 'Content', @sTmp1 OUT
        PRINT @i + ': ' + @sTmp0 + ' : ' + @sTmp1
        -- Navigate back up to the parent:
        EXEC sp_OAMethod @xml, 'GetParent2', @success OUT
        SELECT @i = @i + 1
      END

    PRINT '-----'

    -- Notice that the Content of the "xyz" node is empty.  This is correct.
    -- The "xyz" node has no Content, but 2 direct children

    EXEC @hr = sp_OADestroy @xml


END
GO