Jim Nasby <jim.na...@bluetreble.com> writes: > Rather than this, I think an exclusive-or operator would be a lot more > useful. The only difficulty I run into with CHECK constaints is when I > want to ensure that only ONE condition is true.
"bool != bool" works as XOR. If you need "exactly one of N" you could do something like "(cond1::int + cond2::int + ...) = 1". We could wrap some syntactic sugar around either of these, but it's not clear to me that it'd be any more useful than a custom SQL function. regards, tom lane -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers