Hi On Wed, Jan 27, 2010 at 11:29 PM, Olivier Guilyardi <m...@xung.org> wrote: > Hi, > > I'm working with a polyhierarchical thesaurus, and trying to handle that in > Django. By polyhierarchical, I mean : nodes can have both multiple parents and > children. > > Actually, this is a geographical thesaurus, and yes a location can have > multiple > parents (being across countries, etc..). > > I have read about the Nested set paradigm [1], and would love to use that, > maybe > through django-mptt or django-treebeard. But unless someone shows me how, > nested > sets aren't suitable for polyhierarchical data. > > Currently I have a simple recursive many-to-many mapping. This allows to > establish the poly-relations, but is completely unusable for real use cases. > > For instance, I have a table of "items", with a "location" field which points > to > a location in the thesaurus. > > Now I need to list all items which are located in a given country. > > I just can't filter by country, there's no such field in the items table. And > a > location can be of any level of precision, such as country, region, city, > village, etc.. > > The nested set would be perfect for this, but apparently can't handle multiple > parents. > > Do you see a fast and elegant way to handle this ? > > [1] http://dev.mysql.com/tech-resources/articles/hierarchical-data.html >
Maybe you could take a look at this project? http://bitbucket.org/cmutel/django-directed-acyclic-graph/ Matthias -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
