Fair enough. I do already do that in 8th: you can write extensions which call into 8th code, which as you point out, can call back to SQL. There's even more than one flavor of these extensions. But... You could make the same argument against 'triggers': why not just write the code for them in your own app rather than making the SQL engine do the work? There's nothing special about triggers except that they make referential integrity easier to enforce.