Jeff Davis <pgsql@j-davis.com> writes:
> We can either eliminate the USING variant from opt_class (unless it's
> necessary for some reason or I missed it in the documentation), or we
> can use another word (e.g. WITH or WITH OPERATOR) if you don't like
> CHECK.
Hmm ... we don't seem to have documented the USING noise-word, so it
probably would be safe to remove it; but why take a chance? I don't
particularly agree with Peter's objection to CHECK. There are plenty
of examples in SQL of the same keyword being used for different purposes
in nearby places. Indeed you could make about the same argument to
object to USING, since it'd still be there in "USING access_method"
elsewhere in the same command.
I think that USING is just about as content-free as WITH in this
particular example --- it doesn't give you any hint about what the
purpose of the operator is.
regards, tom lane