Suppose I have the following models/migrations:
class Car < ActiveRecord::Base
belongs_to :manufacturer
validates_presence_of :manufacturer
validates_association :manufacturer
end
class CreateCars < ActiveRecord::Migration
def self.up
create_table cars do |t|
t.column :name, :string
t.column :manufacturer_id, :integer
end
end
class Manufacturer < ActiveRecord::Base
has_many :cars
end
class CreateManufacturers < ActiveRecord::Migration
def self.up
create_table maufacturers do |t|
t.column :name, :string
end
end
Now, I need a form to create new Cars that has two text fields: name,
and manufacturer. I can''t use a select for manufacturer, because there
are far too many of them (let''s pretend). What I can''t figure
out is
how to construct the text_field helper tag in my form such that Rails
understands that the form field doesn''t map directly to a field in the
Car object, but rather to the name field of the car''s Manufacturer
object. Is there even a way to do it? I''m looking for something like
one of these (neither of which work, obviously, but they may help to
clarify what I''m trying to do):
<%= text_field ''car'',
''car.manufacturer.name'' %> or
<%= text_field ''car'',
''car.manufacturer[:name]'' %>
Without the ability to do that, I''m not sure how I could have - for
example - an edit form without writing special code to populate that
field, or how any of the validates_* methods would work. I''ve tried
using fields_for, but it doesn''t work; probably because I''m
not doing
it right. Maybe someone knows how to use fields_for to accomplish the
above? I think what I tried was something like this:
<% fields_for :manufacturer, @car.manufacturer do |m_field| %>
<%= m_field.text_field :name %>
<% end %>
--
Bill Kocik
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One thing you can do is define a pair of methods on the car object something like this (off the top of my head). def manufacturer_name=(value) manufacturer.create(:name => value) end def manufacturer_name manufacturer.name end On May 19, 2:44 pm, "Bill Kocik" <bko...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> Suppose I have the following models/migrations: > > class Car < ActiveRecord::Base > belongs_to :manufacturer > validates_presence_of :manufacturer > validates_association :manufacturer > end > > class CreateCars < ActiveRecord::Migration > def self.up > create_table cars do |t| > t.column :name, :string > t.column :manufacturer_id, :integer > end > end > > class Manufacturer < ActiveRecord::Base > has_many :cars > end > > class CreateManufacturers < ActiveRecord::Migration > def self.up > create_table maufacturers do |t| > t.column :name, :string > end > end > > Now, I need a form to create new Cars that has two text fields: name, > and manufacturer. I can''t use a select for manufacturer, because there > are far too many of them (let''s pretend). What I can''t figure out is > how to construct the text_field helper tag in my form such that Rails > understands that the form field doesn''t map directly to a field in the > Car object, but rather to the name field of the car''s Manufacturer > object. Is there even a way to do it? I''m looking for something like > one of these (neither of which work, obviously, but they may help to > clarify what I''m trying to do): > > <%= text_field ''car'', ''car.manufacturer.name'' %> or > <%= text_field ''car'', ''car.manufacturer[:name]'' %> > > Without the ability to do that, I''m not sure how I could have - for > example - an edit form without writing special code to populate that > field, or how any of the validates_* methods would work. I''ve tried > using fields_for, but it doesn''t work; probably because I''m not doing > it right. Maybe someone knows how to use fields_for to accomplish the > above? I think what I tried was something like this: > > <% fields_for :manufacturer, @car.manufacturer do |m_field| %> > <%= m_field.text_field :name %> > <% end %> > > -- > Bill Kocik--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On May 19, 6:44 pm, dasil003 <gabrie...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> One thing you can do is define a pair of methods on the car object > something like this (off the top of my head). > > def manufacturer_name=(value) > manufacturer.create(:name => value) > end > > def manufacturer_name > manufacturer.name > endWon''t manufacturer.create store a new manufacturer in the manufacturers table? In my case, they''re all pre-defined. Users populating this form aren''t creating a new one, they''re typing the name of one that should already exist, after which I validate. But on that note, I did try something like this: def manufacturer=(m) if m.instance_of? String self.manufacturer = Manufacturer.find_by_name(m) else self.manufacturer = m end end Of course, this resulted in an endless loop. Woops. -Bill Kocik --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On May 19, 7:30 pm, Bill Kocik <bko...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> On May 19, 6:44 pm, dasil003 <gabrie...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > One thing you can do is define a pair of methods on the car object > > something like this (off the top of my head). > > > def manufacturer_name=(value) > > manufacturer.create(:name => value) > > end > > > def manufacturer_name > > manufacturer.name > > end > > Won''t manufacturer.create store a new manufacturer in the > manufacturers table? In my case, they''re all pre-defined.Actually, you''ve pretty much nailed it. I set my form up like: <%= text_field_for ''car'', ''manufacturer_name'' %> And in Car: def manufacturer_name=(m) self.manufacturer = Manufacturer.find_by_name(m) end def manufacturer_name self.manufacturer.name end This seems to do pretty much exactly what I was trying to accomplish, and my validates_presence_of works. The only thing that doesn''t work is validates_associated :manufacturer, because when an invalid manufacturer name is entered it isn''t found in the database, so manufacturer remains nil and the validates_presence_of fails instead. But I can live with that. Thanks for the brain kick. :) -Bill --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---