"ed zappulla" <zappullae_at_rcn.com> wrote in message
news:9r42mp$jv0$1_at_bob.news.rcn.net...
> many countries do not have postal codes. Ireland for one.
>
> country, state, city is the proper key with a null state being valid.
>
>
Didn't know that which given my name is somewhat embarrassing <vbg>.
if you have two records with the same country and city and a null state then
logically they could be the same place and hence violate the uniqueness
requirement for a primary key, or they might not be the same place and so
not violate the uniqueness requirement. who can tell? Certainly not oracle
which is why a primary key must be not null and unique.
--
Niall Litchfield
Oracle DBA
Audit Commission UK
Received on Tue Oct 23 2001 - 11:38:50 CDT
