Στις Thursday 08 April 2010 17:59:01 ο/η Rob Sargent έγραψε: > 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 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 > >> > >> > > > > > > >
-- Achilleas Mantzios -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
