After searching high/low for a Mac tool to create ERD diagrams from existing databases, I finally found this one that works.

Used the beta version and ran into some bugs and "nice to have" features. Corresponded with the author and got a response the next day and the fixes the day after!!! It even included some of my wish list items!

If only more companies had such customer service!

When they complete documentation (eg, how to set up the JDBC data source, etc.), it will even be better!