| From: | Rich Shepard <rshepard(at)appl-ecosys(dot)com> |
|---|---|
| To: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Add Foreign Keys To Table |
| Date: | 2011-07-07 21:12:41 |
| Message-ID: | alpine.LNX.2.00.1107071411480.20399@salmo.appl-ecosys.com |
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| Lists: | pgsql-general |
On Thu, 7 Jul 2011, John R Pierce wrote:
> if your original table has Primary Key of (sta_type, secondary_type) I
> would not expect EITHER of those fields to be unique by themselves....
> Surely there can be more than one of the same sta_type with different
> secondary_type's, just as there could be more than one secondary_type with
> different sta_types.... if either of these fields is unique of and by
> itself, it doesn't make sense to use the combined primary key.
John,
Ah, yes. Of course. That's why the compound primary key is required. I'll
redo the table the proper way.
Thanks,
Rich
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