Re: Unique or Primary Key?
| От | Bruce Richardson |
|---|---|
| Тема | Re: Unique or Primary Key? |
| Дата | |
| Msg-id | 20010503.17004700@usb.cafod обсуждение исходный текст |
| Ответ на | Re: Unique or Primary Key? (GH <grasshacker@over-yonder.net>) |
| Ответы |
RE: Unique or Primary Key?
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| Список | pgsql-general |
On 5/3/01, 2:29:09 AM, GH <grasshacker@over-yonder.net> wrote regarding Re: [GENERAL] Unique or Primary Key?: > Just to expand on Eric's response, a Primary Key directive creates a > unique not null column, whereas a unique column can be null. In this > instance, your columns are already not null, so, as Eric responded, it is > basically the same thing. OK. I was just worried that there might be some more subtle issues regarding query/index optimisation. Besides, I couldn't see much use in creating it as a primary key. How would I ever reference it from another table? -- Bruce
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