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[SQL] Table Design for Hierarchical Data
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#21
 
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Re: [SQL] Table Design for Hierarchical Data -
04-12-2010
, 09:57 AM
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Στις Thursday 08 April 2010 17:59:01 ο/η Rob Sargent *γραψε: The "parent" node in a genealogy is the mother-father tuple, so given that as a singularity it still fits a tree. No, because the child and parent node would be of different schema. On 04/08/2010 12:56 AM, Achilleas Mantzios wrote: Στις Wednesday 07 April 2010 23:33:07 ο/η Yeb Havinga *γραψε: Achilleas Mantzios wrote: Στις Wednesday 07 April 2010 11:06:44 ο/η Yeb Havinga *γραψε: 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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#22
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Believe me: "ego-ma-pa" will correctly define genealogical relationships (at least among humans). |
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,
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Leif Biberg Kristensen
http://solumslekt.org/
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#23
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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. The last sentence is almost like the 'proof by authority' from 36 |
http://jwilson.coe.uga.edu/EMT668/EM...oof/proof.html.
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#24
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Leif Biberg Kristensen wrote: 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. The last sentence is almost like the 'proof by authority' from 36 methods of mathematical proof, see e.g. http://jwilson.coe.uga.edu/EMT668/EM...oof/proof.html. |
<http://www.youtube.com/watch?v=JTcx_IaI8BY>. Sorry that I forgot to mention
that.
regards,
--
Leif Biberg Kristensen
http://solumslekt.org/
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