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 >> >> > > > -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
