Re: primary key index

From: Sim Zacks <sim(at)compulab(dot)co(dot)il>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: primary key index
Date: 2007-05-14 09:32:36
Message-ID: f296td$22jl$1@news.hub.org
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

It is mixture of looking and knowing where to look. I read the section on indexes where it says that
PostGreSQL creates a unique index, but I didn't see an index on the table so I didn't know if it was
implicit or if for some reason my primary keys weren't becoming indexes. I didn't see the create
table documentation which states that it is not necessary to explicitly create them.

Thank you for your help.

> PostgreSQL automatically creates a unique index when a unique constraint
> or a primary key is defined for a table. The index covers the columns that
> make up the primary key or unique columns (a multicolumn index, if appropriate),
> and is the mechanism that enforces the constraint.

Ron Johnson wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On 05/14/07 03:27, Sim Zacks wrote:
>> Is a primary key an implicit index, or if I want to join on that field
>> is it also worthwhile to make an explicit index?
>
> On-line documentation is such a wonderful resource...
>
> http://www.postgresql.org/docs/7.3/interactive/sql-createtable.html
>
> PostgreSQL automatically creates an index for each unique
> constraint and primary key constraint to enforce the uniqueness.
> Thus, it is not necessary to create an explicit index for
> primary key columns.
>
> (Yes, I purposefully used the doc set of an ancient version.)
>
> - --
> Ron Johnson, Jr.
> Jefferson LA USA
>
> Give a man a fish, and he eats for a day.
> Hit him with a fish, and he goes away for good!
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.6 (GNU/Linux)
>
> iD8DBQFGSBOrS9HxQb37XmcRAlhTAKDFekzal8p33SB5oW10NyTiQtkNQACeIXpP
> Y8JuW+MjqIxWqZl86PsIxuw=
> =TxAn
> -----END PGP SIGNATURE-----
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Have you searched our list archives?
>
> http://archives.postgresql.org/
>

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Dmitry Koterov 2007-05-14 10:40:46 Re: TWO SAME TABLES, ONE UPDATED. HOW TO SYNC THE OTHER?
Previous Message Marcel 2007-05-14 09:12:45 tsearch2 problem