| From: | "Roderick A(dot) Anderson" <raanders(at)tincan(dot)org> |
|---|---|
| To: | Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> |
| Cc: | Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Foreign Key Columns And Indices |
| Date: | 2001-02-05 03:22:37 |
| Message-ID: | Pine.LNX.4.10.10102041912350.19984-100000@tincan.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Mon, 5 Feb 2001, Christopher Kings-Lynne wrote:
> Just a quick question, when a column of a table is defined to be a foreign
> key, is it implicitly indexed, or does one still need to explicitly CREATE
> INDEX?
I don't think you can actually declare the column in the table as a
foreign key. A foreign key is a column or columns in another table. For
a single column in the other table I'm pretty sure that column must be
'not null' and 'unique'. An index - other than to inforce uniqueness
(currently how it's done in PostgreSQL?) - has nothing to do with the
foreign key.
Being a mere mortal - not a demi-god of PostgreSQLness - this could be
an over simplification or totally out to lunch.
Rod
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