Believe me: "ego-ma-pa" will correctly define genealogical relationships (at least among humans).
On 04/12/2010 02:14 AM, Achilleas Mantzios wrote: > 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 >>>> >>>> >>> >>> >>> >> > > > -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
