From: | "Grigoriy G(dot) Vovk" <grigoriy(dot)vovk(at)linustech(dot)com(dot)cy> |
---|---|
To: | Cedar Cox <cedarc(at)visionforisrael(dot)com> |
Cc: | <pgsql-sql(at)postgresql(dot)org> |
Subject: | Re: REFERENCES constraint |
Date: | 2001-08-08 17:26:33 |
Message-ID: | 20010808202427.Q574-100000@callisto.internal.linustech.com.cy |
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Thread: | |
Lists: | pgsql-sql |
As for me it is looking as not good normalized structure.
After normalization should not be any questions, I think...
Aug 8, 19:02 +0300, Cedar Cox wrote:
>
> Two questions (maybe they are silly..)
>
> 1. Can a column reference more than one table? (This assumes you use a
> single sequence to generate the IDs for both "tbla" and "tblb". I guess
> you would also have the problem of enforcing a unique index. Say what?!
> A unique index across multiple tables.. absurd :) eg..
>
> CREATE TABLE blah (
> id int4,
> f_id int4 REFERENCES tbla (id) REFERENCES tblb (id)
> )
>
> 2. Can a column reference another column in the same table? eg..
>
> CREATE TABLE bloo (
> id int4,
> p_id int4 REFERENCES bloo (id)
> -- or
> --p_id int4 REFERENCES (id)
> )
>
> I'm guessing the answer is no, in which case I have to fall back to
> writing custom PL/ functions and triggers. Just thought I'd ask anyway.
> It would be nice if it were this easy though...
>
> -Cedar
> p.s. please CC my on this thread.. I'm on vacation (on this list) :0
>
>
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my best regards,
----------------
Grigoriy G. Vovk
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