I have a slow_function. My table has field f, and since slow_function
is slow, I need to denormalize and store slow_function(f) as a field.
What's the best way to do this automatically? Can this be done with
triggers? (On UPDATE or INSERT, SET slow_function_f =
slow_function(new_f) ) How?
Will creating an index on slow_function(f) do this?