-i searched through the news group but couldn''t find the answer for my
problem.
example:
----------- classes ----------
class Car < ActiveRecord::Base
has_one :colour
def after_create()
colour = Colour.new
colour.name = ''colour1''
colour.save
end
end
class Chair < ActiveRecord::Base
has_one :colour
end
class Colour < ActiveRecord::Base
end
-------------- tables ---------
create table cars(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name
varchar(50),colour_id int NOT NULL, primary key(id));
create table chairs(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name
varchar(50),colour_id int NOT NULL);
create table colours(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name
varchar(50));
- i consider it a many to one relation because diferent types of items
are refering to one type (Car and Chair both have colour).
- i wrote the models as above i create a Car object, i save it but
alwayes my colour_id in the database remains 0.
I would appreciate if your could give me a hint.
--
Posted via http://www.ruby-forum.com/.
--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---
Hi I''m absolutely not an expert in this, but I would have expected: class Colour < ActiveRecord::Base belongs_to :chair belongs_to :car end I think that with a has_one relation, you require a belongs_to on the other side of the relation. Darren P. Pantouffe wrote:> -i searched through the news group but couldn''t find the answer for my > problem. > example: > > ----------- classes ---------- > class Car < ActiveRecord::Base > has_one :colour > def after_create() > colour = Colour.new > colour.name = ''colour1'' > colour.save > end > end > > class Chair < ActiveRecord::Base > has_one :colour > end > > class Colour < ActiveRecord::Base > end > -------------- tables --------- > create table cars(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name > varchar(50),colour_id int NOT NULL, primary key(id)); > > create table chairs(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name > varchar(50),colour_id int NOT NULL); > > create table colours(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name > varchar(50)); > > - i consider it a many to one relation because diferent types of items > are refering to one type (Car and Chair both have colour). > - i wrote the models as above i create a Car object, i save it but > alwayes my colour_id in the database remains 0. > I would appreciate if your could give me a hint.-- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Hi In addition to this, isn''t the relation you require in both cases a has_many, i.e. both chairs and cars have many colours, and a colour belongs to a chair or a car? Darren -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Hi and tkns for the reply
i''ve tried with:
class Colour < ActiveRecord::Base
belongs_to :chair
belongs_to :car
end
and modified after_create
def after_create()
colour = Colour.new
colour.name = ''colour1''
colour.save
save() # <- this one
end
my colour_id still remains 0.
- i''m beginner in both databases and ruby. I interpret a has_many
relation as a parent_id colour for the colours table and i don''t think
this is correct.
There''s something wrong in what i''m doing but I
don''t know what. :D
--
Posted via http://www.ruby-forum.com/.
--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---
P. Pantouffe wrote:> Hi and tkns for the reply > > i''ve tried with: > > class Colour < ActiveRecord::Base > belongs_to :chair > belongs_to :car > end > > and modified after_create > def after_create() > colour = Colour.new > colour.name = ''colour1'' > colour.save > save() # <- this one > end > > my colour_id still remains 0. > - i''m beginner in both databases and ruby. I interpret a has_many > relation as a parent_id colour for the colours table and i don''t think > this is correct. > There''s something wrong in what i''m doing but I don''t know what. :DALthough the english doesn''t always read well, the belongs_to goes where the foreign key is. In your case, thats Car or CHair. So Car belongs_to Color, Color has_many Cars Chair belongs_to COlor, Color has_many Chairs As I said you would say a "Car belongs to a colour" in english, but thats how you say it in rails :) A. -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Alan Francis wrote:> ALthough the english doesn''t always read well, the belongs_to goes where > the foreign key is. > > In your case, thats Car or CHair. So > > Car belongs_to Color, Color has_many Cars > Chair belongs_to COlor, Color has_many Chairs > > As I said you would say a "Car belongs to a colour" in english, but > thats how you say it in rails :) > > A.Sorry, that should have been "you *wouldn''t* say...in english", and there probably shouldn''t be quite so many capital letters. Alan -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
P. Pantouffe wrote:> Hi and tkns for the reply > > i''ve tried with: > > class Colour < ActiveRecord::Base > belongs_to :chair > belongs_to :car > end > > and modified after_create > def after_create() > colour = Colour.new > colour.name = ''colour1'' > colour.save > save() # <- this one > end > > my colour_id still remains 0. > - i''m beginner in both databases and ruby. I interpret a has_many > relation as a parent_id colour for the colours table and i don''t think > this is correct. > There''s something wrong in what i''m doing but I don''t know what. :DI take it you mean the colour_id of your new Car remains unchanged? This is what I would expect to happen given the code above, although it will create an entry in the colour table. What you haven''t done is tie the two records together. RoR does a lot of nice things for you, like make associations appear as if they are in the original model. What does this mean? When your creating a new Car, try: new_car = Car.new new_car.colour = Colour.find_or_create_by_name "colour 1" new_car.save (I am no expert either, but I figure hanging out here and trying to solve problems I will learn) -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Hi, thank u for anserwing me. Indeed it works when i say car belongs to color (David must hove some reason for switching it.) and putting the color creation code in a way askegg wrote. - it don''t understand why my code in the after_create() method did not work, the API says that ,,after_create() is called after Base.save on new objects that havent been saved yet (no record exists)", in the code: def after_create() colour = Colour.new colour.name = ''colour1'' ... end colour is the Atribute, isn''t it? -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
P. Pantouffe wrote:> Hi, thank u for anserwing me. > Indeed it works when i say car belongs to color (David must hove some > reason for switching it.) and putting the color creation code in a way > askegg wrote. > - it don''t understand why my code in the after_create() method did not > work, the API says that ,,after_create() is called after Base.save on > new objects that havent been saved yet (no record exists)", in the > code: > > def after_create() > colour = Colour.new > colour.name = ''colour1'' > ... > end > > colour is the Atribute, isn''t it?Then that would need to be @colour. You just created a brand new temporary variable. A. -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
P. Pantouffe wrote:> - it don''t understand why my code in the after_create() method did not > work, the API says that ,,after_create() is called after Base.save on > new objects that haven''t been saved yet (no record exists)", in the > code: > > def after_create() > colour = Colour.new > colour.name = ''colour1'' > ... > end > > colour is the Atribute, isn''t it?The code is called after the record is created, but the current code creates a new entry in the colour table, but does not tie it to the Car record. Strictly speaking, their is no "colour" attribute on the Car object - there is only an association to a Colour object, so you need to pass a Colour object not a string. class Car < ActiveRecord::Base belongs_to :colour def after_create() self.colour = Colour.find_or_create_by_name(''colour 1'') self.save end end --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Alan Francis wrote:>> def after_create() >> colour = Colour.new >> colour.name = ''colour1'' >> ... >> end >> >> colour is the Atribute, isn''t it? > > Then that would need to be @colour. You just created a brand new > temporary variable.@colour = Colour.create(...) would do the trick. But the other way is better :-) A. -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
> - it don''t understand why my code in the after_create() method did not > work, the API says that ,,after_create() is called after Base.save on > new objects that havent been saved yet (no record exists)", in the > code:A record doesn''t have an ID until it''s be saved. So if you save the child before the parent, the parent_id column (colour_id) will be zero by default. -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
thank u all for the info. Best wishes! -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
P. Pantouffe wrote:> thank u all for the info. > Best wishes!No problem, Alan -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---