I just returned from PASS where I first heard about BIML, so this article was very timely. Thank you for this! It's very powerful stuff. I noticed that apparently biml compiler does a lot of things "behind the scenes". For example, we never specified column mapping between the output of the "Conditional Split" and stgUpdates destination. I guess since in this case the column names matched, they were simply mapped based on their names. But what if they were different, which, I suspect, is a more common scenario? We would probably need to write much more code.