From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Shigeru Hanada <shigeru.hanada@gmail.com>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: inherit support for foreign tables
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
 message dated "Mon, 18 Nov 2013 09:36:50 -0500"
Date: Mon, 18 Nov 2013 09:55:24 -0500
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Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Nov 14, 2013 at 12:28 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> 2) Allow foreign tables to have CHECK constraints
>>> Like NOT NULL, I think we don't need to enforce the check duroing
>>> INSERT/UPDATE against foreign table.

>> Really?

> I think it's been previously proposed that we have some version of a
> CHECK constraint that effectively acts as an assertion for query
> optimization purposes, but isn't actually enforced by the system.  I
> can see that being useful in a variety of situations, including this
> one.

Yeah, I think it would be much smarter to provide a different syntax
to explicitly represent the notion that we're only assuming the condition
is true, and not trying to enforce it.

			regards, tom lane


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