Subject: Re: BUG #5926: information schema dtd_identifier for
	element_types, columns, parameters views inconsistent
From: Peter Eisentraut <peter_e@gmx.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Susanne Ebrecht <susanne@2ndQuadrant.com>, Ingmar Brouns
	<swingi@gmail.com>,  pgsql-bugs@postgresql.org
In-Reply-To: <9773.1307545767@sss.pgh.pa.us>
References: <201103111318.p2BDITcL034900@wwwmaster.postgresql.org>
	<4DDCE812.10401@2ndQuadrant.com>  <9773.1307545767@sss.pgh.pa.us>
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Date: Thu, 09 Jun 2011 18:00:30 +0300
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On ons, 2011-06-08 at 11:09 -0400, Tom Lane wrote:
> As far as I can tell from the spec, dtd_identifier
> ought to be the identifier of the element type, while
> collection_type_identifier should be a made-up identifier for the
> array type.  That would make the sample query given in the docs
> correct.

But it's collection_type_identifier that you join against, say, columns,
so you can resolve the element type of column types.  So
collection_type_identifier must match the dtd_identifier schema of
columns etc., whereas element_types.dtd_identifier is not joinable
against anything.