If someone made tools that were simple, flexible, and easy to use for exposing a SQL wrapper around your underlying business logic layer, then I would happily u

If someone made tools that were simple, flexible, and easy to use for exposing a SQL wrapper around your underlying business logic layer, then I would happily use those tools, probably alongside stored procedures to avoid arbitrary client queries. As far as I know they don't exist. Things like foreign data wrappers in postgres are a pain because you have to drag in the entirety of postgres and because they're difficult to extend with your own functionality.