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From: "Phil Endecott" <spam_from_postgresql_sql@chezphil.org>
To: Franco Bruno Borghesi <franco@akyasociados.com.ar>,
	pgsql-sql@postgresql.org
Subject: Re: Need indexes on inherited tables?
Date: Sat, 26 Jun 2004 18:30:26 -0400
Message-Id: <8141987@chezphil.org>
In-Reply-To: <1088283980.1215.19.camel@taz.oficina>
References: <1902614@chezphil.org> <1088283980.1215.19.camel@taz.oficina>

I asked if derived tables use primary key indexes generated in the base tables that they inherit from.

Franco Bruno Borghesi replied:
> [the derived table] is not inheriting any indexes, neither the
> primary key constraint.

OK, thanks!  I had come to the conclusion that it was not using the index, but I'm really surprised to hear that the primary key constraint that I define in a base table is not inherited.  Are any constraints inherited?  What happens if I declare a single-column primary key?  What if I declare a "not null" constraint or a "check" constraint in a base table?

Having to replicate the constraints and indexes for each derived table is a pain - lots of error-prone typing - but there is a more serious problem: how can I ensure that these keys are unique across all of the derived tables?  (i.e. if T1 and T2 inherit from B, and B's primary key is (id,xx), then I want there to be at most one row in (T1 union T2) that has any value of (id,xx).)

Is this a possible area for future enhancements?

Regards,

--Phil.