I'm not sure I understand your question: it seems from the link you provided, that this article (for example) gives you all you need to do this:
http://articles.sitepoint.com/article/hierarchical-data-database/2 Actually, several of the links seem to be of similar usefulness... The php examples use classes (but we don't have an ORM, so data doesn't map that way - the DAL is closer to the data model, so the links provide you fairly direct ways to implement all you want, I think). On Thu, Oct 15, 2009 at 12:01 AM, Vasile Ermicioi <[email protected]> wrote: > Hi, > But what about a more efficient tree implementation (at least for > retrieving ) like nested sets or materialized paths. > PhpDoctrine has an implementation > http://www.doctrine-project.org/documentation/manual/1_1/en/hierarchical-data#nested-set > <http://www.doctrine-project.org/documentation/manual/1_1/en/hierarchical-data#nested-set>This > was why I used doctrine in a few projects. > Even for implementing by myself I don't know how to do that, is there a > method to extend default table behavior, are there some events like > before_insert, or something like that? (sorry if it is a basic question, I > am still new to web2py, but was interested by this question) > > > On Thu, Oct 15, 2009 at 1:05 AM, Yarko Tymciurak <[email protected]>wrote: > >> On Wed, Oct 14, 2009 at 4:44 PM, Giedrius <[email protected]> wrote: >> >>> >>> How i can make recursive one to many relation? I want to have >>> generalized categories like: Programing langauge / High level / >>> Python, Programing langauge / Low level / C, Programing langauge / >>> High level / PHP, Programing langauge / Low level / ASM and so on.. >>> I tried to like this, but got an error: >>> >>> db.define_table('category', >>> Field('name'), >>> Field('parent_id', db.category), >>> Field('info')) >>> >> >> To do self-reference or forward reference, use this form: >> >> Field('parent_id', 'reference category'), >> >> >> You can find more about this in section 6.13 of the Manual, >> "Self-Reference and Aliases" >> ( http://www.web2py.com/examples/default/docs ) >> >> - Yarko >> >> >>> >>> >>> Traceback (most recent call last): >>> File "/home/giedrius/web2py/gluon/restricted.py", line 178, in >>> restricted >>> exec ccode in environment >>> File "/home/giedrius/web2py/applications/shop/models/db.py", line >>> 74, in <module> >>> Field('parent_id', db.category), >>> File "/home/giedrius/web2py/gluon/sql.py", line 537, in __getattr__ >>> return dict.__getitem__(self,key) >>> KeyError: 'category' >>> >>> >>> >> >> >> > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py-users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
