Albe Laurenz <laurenz.a...@wien.gv.at> writes: > Darren Duncan wrote: >> I propose that this be generalized so that constraints may instead be >> nullary, >> that is, range over zero or more attributes/columns instead.
> Since an imagined zero-column query would have an empty set of > result columns, you could with equal force argue that these columns > satisfy the condition or not, because the members of the empty > set have all the properties you desire. The semantics of a zero-column foreign key seem even less well defined. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers