PostgreSQL Discussion - Re: PRIMARY KEY on a *group* of columns imply that each column is

You are viewing an archived Text-only version of the thread. To view this thread in it's original format and/or if you want to reply to this thread please [click here]

Author

Re: PRIMARY KEY on a *group* of columns imply that each column is

Scott Marlowe

2005-04-27, 9:23 am

On Wed, 2005-04-27 at 02:12, Stephane Bortzmeyer wrote:
> On Tue, Apr 26, 2005 at 03:48:44PM -0500,
> Scott Marlowe < smarlowe@g2switchwor
ks.com> wrote
> a message of 26 lines which said:
>
>
> Yes, PostgreSQL is right and implement the standard. Now, what's the
> rationale for the standard? I understand it for a single column but,
> for several columns, it should be still possible to have different
> tuples, such as (3, NULL) and (5, NULL) for instance.

Since NULL <> NULL, that means you could then have

(5,NULL) and (5,NULL) since the two NULLS aren't equal.

---------------------------(end of broadcast)---------------------------
TIP 2: you can get off all lists at once with the unregister command
(send "unregister YourEmailAddressHere
" to majordomo@postgresql
.org)

Sponsored Links