Re: operator exclusion constraints [was: generalized index constraints]

On Wed, 2009-09-23 at 15:10 +0300, Peter Eisentraut wrote:
> Using CHECK as part of the syntax of an EXCLUSION constraint will surely
> confuse the whole thing with CHECK constraints.
> 
> USING OPERATOR is available, I think.

USING won't work because one of the ways to specify the opclass in an
index_elem is something like:

  CREATE INDEX foo_idx on foo (i USING int4_ops);

which appears to be undocumented, and it's not obvious to me why that is
useful. The normal way is just:

  CREATE INDEX foo_idx on foo (i int4_ops);

Because I am allowing any index_elem for exclusion constraints, that
conflicts with the word USING.

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.

Regards,
	Jeff Davis