Received: from localhost (unknown [200.46.204.183])
	by mail.postgresql.org (Postfix) with ESMTP id 042686338CC;
	Mon, 20 Apr 2009 11:28:10 -0300 (ADT)
Received: from mail.postgresql.org ([200.46.204.86])
	by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024)
	with ESMTP id 19470-02; Mon, 20 Apr 2009 11:28:08 -0300 (ADT)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.6
X-Greylist: from auto-whitelisted by SQLgrey-1.7.6
Received: from fetter.org (start.fetter.org [66.92.188.65])
	by mail.postgresql.org (Postfix) with ESMTP id 452C1633D8D;
	Mon, 20 Apr 2009 11:27:47 -0300 (ADT)
Received: by fetter.org (Postfix, from userid 500)
	id 30B3EFBC994; Mon, 20 Apr 2009 07:27:45 -0700 (PDT)
Date: Mon, 20 Apr 2009 07:27:45 -0700
From: David Fetter <david@fetter.org>
To: Robson Fidalgo <rdnf@cin.ufpe.br>
Cc: pgsql-docs@postgresql.org, pgsql-general@postgresql.org
Subject: Re: [GENERAL] Postgresql 8.3X supports Arrays of Composite
	Types?
Message-ID: <20090420142744.GM4235@fetter.org>
References: <41534c40904191403m2eeabc27tc4bc6ce206c87464@mail.gmail.com>
	<20090419235619.GB10700@fetter.org>
	<41534c40904200413y60b140a4wf4305c36efd214c0@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <41534c40904200413y60b140a4wf4305c36efd214c0@mail.gmail.com>
User-Agent: Mutt/1.5.18 (2008-05-17)
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none
X-Spam-Level: 
X-Archive-Number: 200904/45
X-Sequence-Number: 5133

On Mon, Apr 20, 2009 at 08:13:15AM -0300, Robson Fidalgo wrote:
> Hi David,
> 
> Thanks for your help, but I want a relational-object solution.

You can have one without denormalizing.  Just use VIEWs and rewrite
RULEs for INSERTs, UPDATEs and DELETEs on them.

> The solution presented by Tom Lane (Thanks Tom!!!!) runs very well
> and it is a relational-object implementation (I suggest put a
> similar example in postgresql 8.3X documentation).

The docs already contain an example:

http://www.postgresql.org/docs/current/static/rules-update.html

There are excellent reasons not to encourage people to do only half
the job.  One part, the smaller part, is presenting an interface which
one part of your OO code can talk to.  The other part, and the much
larger one, is having a well-indexed, normalized data store
underneath.

Example: Under the store-the-compound system you're proposing, how do
you find all the people who have a common prefix?  Answer: Normalize.
If you need that answer quickly, you're looking at down time and DDL
changes.  The questions you ask about the data are impossible to know
in advance, so normalized data helps you deal with that.

Cheers,
David.
-- 
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
Skype: davidfetter      XMPP: david.fetter@gmail.com

Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate