Provably? I'll leave that up to the academics. Practically? I've never had someone throw a problem at me I couldn't model in SQL. Not saying I can guarantee pe

Provably? I'll leave that up to the academics. Practically? I've never had someone throw a problem at me I couldn't model in SQL. Not saying I can guarantee performance, but in terms of abstract modeling I've never encountered something that can't be done "clean". I'd like to use the analogy of painting. What can't you paint on that canvas that isn't trivially-hindered by the available media? Can you actually describe that space of things? In my estimation, premature optimization is why most people can't work in these terms. You wind up with a tuple like WorldObjects and immediately go off the deep end about a billion row scale before you are done naming things.