Date: Wed, 9 Oct 2013 15:31:49 -0700 (PDT)
From: David Johnston <polobo@yahoo.com>
To: pgsql-sql@postgresql.org
Message-ID: <1381357909835-5773925.post@n5.nabble.com>
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Subject: Re: Question about index/constraint definition in a table
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JORGE MALDONADO wrote
> I have a table as follows:
> ------------------------------------------------
> Table Artist Colaborations
> ------------------------------------------------
> * car_id (integer field, primary key)
> * car_song (integer field, foreign key, foreign table is a catalog of
> songs)
> * car_artist (integer field, foreign key, foreign table is a catalog of
> artists)
> 
> So, I added 2 indexes to improve JOIN in queries:
> 1. An index for car_song which accepts duplicates.
> 2. An index for car_artist which accepts duplicates.
> 
> Now, the combination of "car_song + car_artist" cannot be duplicated so I
> think that adding a constraint on these 2 fields is the solution.
> 
> My question: Is this the correct way to go?
> 
> Respectfully,
> Jorge Maldonado

Yes.  Why is it this is a question for you?

Also, the car_id field becomes pointless since your new constraint is the
true and natural PK.

David J.


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