From: Rob Sargent <robjsargent@gmail.com>
To: pgsql-sql@postgresql.org
Subject: Re: Table Design for Hierarchical Data
Date: Thu, 08 Apr 2010 08:59:01 -0600
Message-ID: <4BBDEF35.6040308@gmail.com> (raw)
In-Reply-To: <201004080956.06446.achill@matrix.gatewaynet.com>
References: <n2i5ab13581004061033j4ed25734xd0504cb95a1fc092@mail.gmail.com>
<201004071139.42140.achill@matrix.gatewaynet.com>
<4BBCEC03.3050100@gmail.com>
<201004080956.06446.achill@matrix.gatewaynet.com>
The "parent" node in a genealogy is the mother-father tuple, so given
that as a singularity it still fits a tree.
On 04/08/2010 12:56 AM, Achilleas Mantzios wrote:
> Στις Wednesday 07 April 2010 23:33:07 ο/η Yeb Havinga έγραψε:
>> Achilleas Mantzios wrote:
>>> Στις Wednesday 07 April 2010 11:06:44 ο/η Yeb Havinga έγραψε:
>>>
>>>> Achilleas Mantzios wrote:
>>>>
>>>>> You could also consider the genealogical approach, e.g.
>>>>>
>>>>>
>>>>> The parents of any node to the root, i.e. the path of any node to the root are depicted as
>>>>> parents[0] : immediate parent
>>>>> parents[1] : immediate parent of the above parent
>>>>>
>>>>>
>>>> What I have more than one parent?
>>>>
>>>
>>> Then it is no longer neither a tree, nor a hierarchical structure, but rather a graph.
>>> This a totally different problem.
>>>
>> My question was actually an attempt to point at the inability of what
>> you call the 'genealogical approach' database design to store
>> information of more than one parent.
>
>
> Are you suggesting that we should change our definition of trees ADT, just because it does not
> fit the mere detail that humans have two parents?
> Or are you just suggesting that the "genealogical" term is inaccurate?
>
> Take a look here: www.tetilab.com/roberto/pgsql/postgres-trees.pdf
>
>>
>> regards,
>> Yeb Havinga
>>
>>
>
>
>
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Subject: Re: Table Design for Hierarchical Data
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