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Message-ID: <46B2D823.7020700@gmail.com>
Date: Fri, 03 Aug 2007 09:24:19 +0200
From: =?ISO-8859-1?Q?Dani_Casta=F1os?= <danitao.mailists@gmail.com>
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CC: pgsql-sql@postgresql.org
Subject: Re: Foreign Key inter databases
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	<e7e0a2570708021223n1e6e234dtbd6f04f6e9089189@mail.gmail.com>
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Josh Tolley escribió:
> On 8/2/07, Dani Castaños <danitao.mailists@gmail.com> wrote:
>   
>> Hi all!
>>
>> Is it possible to have a foreign key where referenced table is in
>> another database?
>>
>> Thank you in advance
>>
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>>     
>
> Unless you use things like dblink to make two separate databases think
> they're one database, you really can't do anything where one database
> depends on another. Your best bet, if you can have both data sets on
> the same machine, is to stick them in two separate schemas, and then
> you can have foreign keys on a table in one schema referencing a table
> in another schema. That's (in part) what schemas are for in the first
> place -- to separate logically distinct data sets while allowing
> accesses between the two when necessary.
>
> If for whatever reason having all the data on one machine isn't
> possible, you can try using dbi-link or dblink to create links between
> the two databases and do foreign keys that way, but I've never used
> either, so that might not work/make sense/be possible, etc.
>
> -Josh
>   

Thanks Josh!
I use dblinks for queries, but I'm pretty sure you can't use it in 
constraints definitions.
My situation is that I have one main database and many customer's 
databases. In main database there is a languages table, and customers 
databases must use the language_id. Then, I don't want to create 
languages table in each customer db, that's the reason why i was trying 
to do a foreign key from customer db to main db.