Received: from maia.hub.org (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id D61E4633F01 for ; Mon, 12 Apr 2010 12:30:33 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 33028-05 for ; Mon, 12 Apr 2010 15:30:22 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mail42.e.nsc.no (mail42.e.nsc.no [193.213.115.42]) by mail.postgresql.org (Postfix) with ESMTP id AC3DC63387E for ; Mon, 12 Apr 2010 12:30:21 -0300 (ADT) Received: from balapapa.localnet (42.185.16.62.customer.cdi.no [62.16.185.42]) (authenticated bits=0) by mail42.nsc.no (8.14.3/8.14.3) with ESMTP id o3CFUJ9n006507 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Mon, 12 Apr 2010 17:30:20 +0200 (MEST) From: Leif Biberg Kristensen To: pgsql-sql@postgresql.org Subject: Re: Table Design for Hierarchical Data Date: Mon, 12 Apr 2010 17:30:18 +0200 User-Agent: KMail/1.12.4 (Linux/2.6.32-gentoo-r7; KDE/4.3.5; i686; ; ) References: <201004121114.10189.achill@matrix.gatewaynet.com> <4BC334E2.6020600@gmail.com> In-Reply-To: <4BC334E2.6020600@gmail.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201004121730.18837.leif@solumslekt.org> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.183 tagged_above=-10 required=5 tests=AWL=-0.283, BAYES_00=-1.9 X-Spam-Level: X-Archive-Number: 201004/44 X-Sequence-Number: 33971 On Monday 12. April 2010 16.57.38 Rob Sargent wrote: > Believe me: "ego-ma-pa" will correctly define genealogical relationships > (at least among humans). Yes, but a family tree is not a hierarchical tree as defined in database theory. Believe me: I'm a genealogist. Hint: Where is the root node of a family tree? Old Adam & Eve? On the other hand, a pedigree may be considered a true binary tree with a root node, the proband. regards, -- Leif Biberg Kristensen http://solumslekt.org/