Re: Avoiding surrogate keys

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От Philippe Lang
Тема Re: Avoiding surrogate keys
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Msg-id 8AE5A725DAF7364F97FF75D99E45B65740B3A79A@SBS1.attiksystem.local
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Ответ на Avoiding surrogate keys  (Thom Brown <thombrown@gmail.com>)
Ответы Re: Avoiding surrogate keys
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Hi,

I think nobody mentioned Object-Relational mappers. If you intend to used one (or think you may be using one in the
future),using surrogate keys is more straightforward, if not necessary. 

Best regards,

-------------------------------------------------------------
Attik System              web  : http://www.attiksystem.ch
Philippe Lang             phone: +41 26 422 13 75
rte de la Fonderie 2      gsm  : +41 79 351 49 94
1700 Fribourg             pgp  : http://keyserver.pgp.com


> -----Message d'origine-----
> De : pgsql-general-owner@postgresql.org [mailto:pgsql-general-
> owner@postgresql.org] De la part de Thom Brown
> Envoyé : mercredi 21 avril 2010 21:01
> À : PGSQL Mailing List
> Objet : [GENERAL] Avoiding surrogate keys
>
> I think I know what I plan to do, but want to throw this out there to
> see if there are differing points of view.
>
> I have a mailing list table, and 2 of the columns contain values which
> have to be from a list.  These are country and status.  There are 237
> possible countries and 3 possible statuses.  Now I know some people
> would assign a sequence ID (surrogate key) to the country and status
> values, and have them looked up in separate tables to get the textual
> value, but I think I'll still have those tables, just without an ID
> column, so 1 column for both the countries and statuses tables.  This
> means storing the proper value in the main table.
>
> So instead of
>
> name, email, country, status
> 'mr smith', 'emailaddress@example.com', 44, 2
> 'mrs jones', 'me@emailcompany.com', 21, 1
>
> I'd have
>
> name, email, country, status
> 'mr smith', 'emailaddress@example.com', 'China', 'Registered'
> 'mrs jones', 'me@emailcompany.com', 'Belgium', 'Unconfirmed'
>
> The values of course would be constrained by foreign key lookup to
> their associated tables.
>
> Are there any serious downsides to this?  If so, what would you
> recommend?
>
> Thanks
>
> Thom

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