is it possible to have a model be belong to itself? say i have a category, and the category can be a subcategory of another category (or it might be a parent category).. is this possible, and does it make sense? something like: class Category < ActiveRecord::Base has_many: categories end i kinda think it would make more sense to use a subcategory model.. but the system i am deriving from (which was written in php) is combining the models.. thanks! -- Posted via http://www.ruby-forum.com/.
Sergio Ruiz wrote:> is it possible to have a model be belong to itself? > > say i have a category, and the category can be a subcategory of another > category (or it might be a parent category)..http://github.com/collectiveidea/awesome_nested_set/> is this possible, and does it make sense?Yes, it makes sense.> something like: > > class Category < ActiveRecord::Base > has_many: categories > end > > i kinda think it would make more sense to use a subcategory model.. but > the system i am deriving from (which was written in php) is combining > the models..No. As you''ll see from the above plugin using one model does make more sense. -- Posted via http://www.ruby-forum.com/.
Robert Walker wrote:> Sergio Ruiz wrote: >> is it possible to have a model be belong to itself?There is also the http://github.com/rails/acts_as_tree/ plugin that implements a simple tree structure and may be adequate for your needs. -- Posted via http://www.ruby-forum.com/.
you can read rails guides. http://guides.rubyonrails.org/association_basics.html#polymorphic-associations class Employee < ActiveRecord::Base has_many :subordinates, :class_name => "Employee", :foreign_key => "manager_id" belongs_to :manager, :class_name => "Employee" end With this setup, you can retrieve @employee.subordinates and @employee.manager. 2009/10/27 Sergio Ruiz <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>:> > is it possible to have a model be belong to itself? > > say i have a category, and the category can be a subcategory of another > category (or it might be a parent category).. > > is this possible, and does it make sense? > > something like: > > class Category < ActiveRecord::Base > has_many: categories > end > > i kinda think it would make more sense to use a subcategory model.. but > the system i am deriving from (which was written in php) is combining > the models.. > > thanks! > -- > Posted via http://www.ruby-forum.com/. > > > >-- tommy xiao E-mail: xiaodsATgmail.com
thanks, guys.. installed awesome_nested_set now.. playing with it.. looks cool.. i am guessing that there is no drop in method of using this with active_scaffold.. correct? anyway.. this looks great! thanks! -- Posted via http://www.ruby-forum.com/.
Sergio Ruiz wrote:> > thanks, guys.. installed awesome_nested_set now.. playing with it.. > looks cool..awesome_nested_set is great. If you''re not already familiar with nested sets, make sure to read Joe Celko''s and Vadim Tropashko''s introductory articles.> > i am guessing that there is no drop in method of using this with > active_scaffold.. correct?Probably. But parent_id shouldn''t present much trouble with ActiveScaffold.> > anyway.. > > this looks great! > > thanks!Best, -- Marnen Laibow-Koser http://www.marnen.org marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org -- Posted via http://www.ruby-forum.com/.