From: | David G Johnston <david(dot)g(dot)johnston(at)gmail(dot)com> |
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To: | pgsql-novice(at)postgresql(dot)org |
Subject: | Re: Advice on index and constraint definition |
Date: | 2014-09-21 01:55:02 |
Message-ID: | 1411264502294-5819815.post@n5.nabble.com |
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Lists: | pgsql-novice |
JORGE MALDONADO wrote
> Thanks for your answer. I am a DB novice and I still have questions, I
> would like you to explain a bit more about the following:
>
> " I'd generally question a design that uses 5 foreign keys on a matching
> table"
>
> Does this mean that my table with 5 foreign keys should have fewer foreign
> keys? How could I achieve this goal if such a table depends on 5 other
> tables? Maybe a must take into account a redesign of this precise table.
My point is a single table relating five other individual tables is quite
probably not properly normalized. If you are using multi-column primary
keys then the presence of 5 columns might only represent 2 source tables
which would be more 'normal'.
This kind of table typically is used for a direct many-to-many relationship
so having 5 foreign keys would definitely complicate the logic.
David J.
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