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
