From: Achilleas Mantzios <achill@matrix.gatewaynet.com>
Organization: Dynacom Tankers Mgmt
To: pgsql-sql@postgresql.org
Subject: Re: Table Design for Hierarchical Data
Date: Thu, 8 Apr 2010 08:56:06 +0200
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Cc: Yeb Havinga <yebhavinga@gmail.com>
References: <n2i5ab13581004061033j4ed25734xd0504cb95a1fc092@mail.gmail.com>
	<201004071139.42140.achill@matrix.gatewaynet.com>
	<4BBCEC03.3050100@gmail.com>
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=CE=A3=CF=84=CE=B9=CF=82 Wednesday 07 April 2010 23:33:07 =CE=BF/=CE=B7 Yeb=
 Havinga =CE=AD=CE=B3=CF=81=CE=B1=CF=88=CE=B5:
> Achilleas Mantzios wrote:
> > =CE=A3=CF=84=CE=B9=CF=82 Wednesday 07 April 2010 11:06:44 =CE=BF/=CE=B7=
 Yeb Havinga =CE=AD=CE=B3=CF=81=CE=B1=CF=88=CE=B5:
> >  =20
> >> Achilleas Mantzios wrote:
> >>    =20
> >>> 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
> >>>  =20
> >>>      =20
> >> What I have more than one parent?
> >>    =20
> >
> > Then it is no longer neither a tree, nor a hierarchical structure, but =
rather a graph.
> > This a totally different problem.
> >  =20
> My question was actually an attempt to point at the inability of what=20
> you call the 'genealogical approach' database design to store=20
> 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

>=20
> regards,
> Yeb Havinga
>=20
>=20


=2D-=20
Achilleas Mantzios