Suppose I have a belongs_to relationship and the thing it belongs to, belongs in turn to something else. For example, I would like to do: belongs_to :city belongs_to: :county, :through => :city While it is not too much trouble to do obj.city.county, there are times when I need to iterate through the attributes and include this second-order attribute. Special code to handle this messes up my nice, clean iteration. How have others accomplished this? Steven -- Posted via http://www.ruby-forum.com/.
Steven Talcott Smith wrote:> Suppose I have a belongs_to relationship and the thing it belongs to, > belongs in turn to something else. > > For example, I would like to do: > > belongs_to :city > belongs_to: :county, :through => :city > > While it is not too much trouble to do obj.city.county, there are times > when I need to iterate through the attributes and include this > second-order attribute. Special code to handle this messes up my nice, > clean iteration. > > How have others accomplished this? > > > StevenI wish this would be added to Core. I do the same thing all the time. For now... Class YourObj def county city.county end end -- Posted via http://www.ruby-forum.com/.
Yeah, I recently started playing around with has_many :through and was surprised that belongs_to :through doesn''t exist. Seems like it should. Joe -- Posted via http://www.ruby-forum.com/.
BTW, anybody file a request ticket? Looks like dev.rubyonrails.org is still having problems... Joe -- Posted via http://www.ruby-forum.com/.
On 7/23/06, Joe <joe@yahoo.com> wrote:> Yeah, I recently started playing around with has_many :through and was > surprised that belongs_to :through doesn''t exist. Seems like it should. > > Joehas_one :through, yes. belongs_to :through, no. I''ll see about getting it in for the next rails release, but I''ve been pretty busy and I personally haven''t needed it. Course if someone wants to step up to the challenge I''ll be more then happy to review a patch and commit if it''s good. -- Rick Olson http://techno-weenie.net
Rick Olson wrote:> On 7/23/06, Joe <joe@yahoo.com> wrote: >> Yeah, I recently started playing around with has_many :through and was >> surprised that belongs_to :through doesn''t exist. Seems like it should. >> >> Joe > > has_one :through, yes. belongs_to :through, no. I''ll see about > getting it in for the next rails release, but I''ve been pretty busy > and I personally haven''t needed it. Course if someone wants to step > up to the challenge I''ll be more then happy to review a patch and > commit if it''s good.Hey Rick, Why no for belongs_to :through? I''m currently working on an app where it seems like it''d make sense, but perhaps I need enlightening ;). Joe -- Posted via http://www.ruby-forum.com/.
> Hey Rick, > > Why no for belongs_to :through? I''m currently working on an app where it > seems like it''d make sense, but perhaps I need enlightening ;). > > JoeBecause belongs_to is for a foreign key thats in the current table. If you''re going :through a model, it''s not the same and has_one should be used. -- Rick Olson http://techno-weenie.net
I wrote a some connected_to code that does:
Say you have a model called TrainingItem that belongs_to a
:calendar_item
You can call TrainingItem connected_to :calendar_item, :date, which will
make @training_item.date work like @training_item.calendar_item.date.
It''s code that I slapped into my model, rather than pluginising, and it
doesn''t add itself to reflects_on_all_associations, but it works
(rather
crudely) for me.
This is the code:
def self.connected_to(external, field, external_class = external)
external_model = external.camelcase
column field, external_model.to_c.columns.find{|x| x.name ==
field.to_s }.type
getter_method = <<-END_GETTER
def #{field}
return self.#{external}.#{field} if self.#{external}
end
END_GETTER
setter_method = <<-END_SETTER
def #{field}=(to_set)
if self.#{external}
self.#{external}.update_attribute(:#{field}, to_set)
else
self.#{external} = #{external_model}.create(:#{field} => to_set)
end
end
END_SETTER
def [](field)
self.send(field) rescue nil
end
def []=(field, to_set)
eval("self.#{field} = to_set")
end
self.module_eval(getter_method)
self.module_eval(setter_method)
end
Note: .to_c is a custom method I defined that basically does
Object.const_get(self) return nil (if I recall correctly).
--
Posted via http://www.ruby-forum.com/.
On Monday, July 24, 2006, at 9:49 AM, Yehuda Katz wrote:>I wrote a some connected_to code that does: > >Say you have a model called TrainingItem that belongs_to a >:calendar_item > >You can call TrainingItem connected_to :calendar_item, :date, which will >make @training_item.date work like @training_item.calendar_item.date. > >It''s code that I slapped into my model, rather than pluginising, and it >doesn''t add itself to reflects_on_all_associations, but it works (rather >crudely) for me. > >This is the code: > > def self.connected_to(external, field, external_class = external) > external_model = external.camelcase > column field, external_model.to_c.columns.find{|x| x.name =>field.to_s }.type > getter_method = <<-END_GETTER > def #{field} > return self.#{external}.#{field} if self.#{external} > end > END_GETTER > setter_method = <<-END_SETTER > def #{field}=(to_set) > if self.#{external} > self.#{external}.update_attribute(:#{field}, to_set) > else > self.#{external} = #{external_model}.create(:#{field} => to_set) > end > end > END_SETTER > def [](field) > self.send(field) rescue nil > end > def []=(field, to_set) > eval("self.#{field} = to_set") > end > self.module_eval(getter_method) > self.module_eval(setter_method) > end > >Note: .to_c is a custom method I defined that basically does >Object.const_get(self) return nil (if I recall correctly). > >-- >Posted via http://www.ruby-forum.com/. >_______________________________________________ >Rails mailing list >Rails@lists.rubyonrails.org >http://lists.rubyonrails.org/mailman/listinfo/railsCan''t you already do this? class Item < AR:Base has_many :widgets delegate :thingees, :widgets def contents self.thingees # returns self.widgets.thingees end end _Kevin www.sciwerks.com -- Posted with http://DevLists.com. Sign up and save your mailbox.