Re: Table Design for Hierarchical Data

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?
>
The latter, but rethinking it, why would genealogical be a bad word when
applied to graph algorithm 'stuff' when words like parent, child,
ancestor, sibling are common use. When I read 'genealogical' I had only
the connotation 'family relations' in mind. I suspect that if looking at
the definition of the word genealogy alone, it could very well include
the study of single parent transitive relationships. However, not
exclusively, so yes, IMHO something called the genealogical approach
should not preclude polyhierarchies.

regards
Yeb Havinga