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constraint question

From: mwaples(at)optusnet(dot)com(dot)au
To: Pgsql-novice <pgsql-novice(at)postgresql(dot)org>
Subject: constraint question
Date: 2001-01-03 10:37:27
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Lists: pgsql-novice
I have a table category with columns -
category_id , main_id

I would like to check that the main_id value exists in category_id in
any row of the table category.

Is it possible to have a foreign key referring to the current table ?
Or should I be using a trigger to do it ?

I'm thinking I have to use a trigger to do it - but want to make sure.

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Subject: Re: constraint question
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Subject: Re: ColdFusion sez this is valid SQL

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