OPENXML, Convert Base64 to Binary - sql

Question

For an import/export process, we put binary data into XML as Base64 encoded strings. The issue came up when getting the values back out...
We're using OPENXML because performance on 2005/2008 is horrid using nodes() - it doesn't scale well at all. They fixed the performance issue in SQL Server 2012, but for the sake of legacy support (2005+) it's not a realistic option, and MS doesn't appear to want to backport things (assuming even possible).
Here's some relevant info on the subject.
Ideally, I'm looking for a single SQL statement using OPENXML to shred an XML document that contains binary data encoded to Base64, and provide a result set there that data is correctly rendered as binary data. I have one solution that doesn't use nodes, hoping someone has something better.

Answer 1

You can specify your column as XML and use .value to get the data as varbinary.
Something like this.
declare #XML xml
set #XML =
'<root>
<item>
<ID>1</ID>
<Col>Um93MQ==</Col>
</item>
<item>
<ID>2</ID>
<Col>Um93Mg==</Col>
</item>
</root>'
declare #idoc int
exec sp_xml_preparedocument #idoc out, #xml
select T.ID,
T.Col.value('.', 'varbinary(max)')
from openxml(#idoc, '/root/item', 2)
with (ID int,
Col xml) as T
exec sp_xml_removedocument #idoc
Or you could make use of CLR (if that is an option for you) something like this:
using System;
using System.Text;
public class CLRTest
{
public static byte[] ConvertBase64ToBinary(string str)
{
if (str == null)
{
return null;
}
return Convert.FromBase64String(str);
}
}