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From: Alvaro Herrera <[email protected]>
To: JORGE MALDONADO <[email protected]>
Cc: pgsql-novice <[email protected]>
Subject: Re: Unique Constraint vs Unique Index
Date: Tue, 5 May 2020 16:32:29 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAAY=A7-2us_KLeqeYO98qfg0zOW1+2rHzscDvC-ZpWEOMdYYRg@mail.gmail.com>

On 2020-May-05, JORGE MALDONADO wrote:

> I have been reading about "unique constraint" and "unique index" in
> PostgreSQL documentation and also did some search in Google. However, it is
> not very clear to me which one to use or when to use one or the other. I
> understand that a "unique constraint" creates a "unique index" under the
> hood. So, at the end, both will check for duplicate records based on the
> field(s) specified for the unique constraint and the unique index.
> 
> What would be a guideline about when to use one or the other?

BTW you already asked this in October 2013 and got good answers.

https://postgr.es/m/CAAY=A78oJ--0aPm4E6ASJ32Z3UHk0nOqHQ_SvrtjOmq7i=UKDQ@mail.gmail.com

You had already asked in July 2013, too.

https://postgr.es/m/CAAY=A78V1gCxC6VEU4_G8e0XouT=c64RA2GaSfGE8MEy3=33_g@mail.gmail.com

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services





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