Relation n->m : uninitialized constant User::UserHasPin

[xkram]

Bonjour,

Je suis confronté à un problème dans le cadre de mon application rails.

Voici mon model concernant la base de donnée (sous SQLite) :


J'ai en effet l'exception suivante : (je voulais juste faire un test pour voir si j'arrive à compter le nombre pins pour un utilisateur)

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NameError in Users#show
 
Showing /app/views/shared/_users_pins.html.erb where line #3 raised:
 
uninitialized constant User::UserHasPin
Extracted source (around line #3):
 
1: <% @user ||= current_user %>
2: <div class="stats">
3:  <%= @user.pins_id.count %>
4: </div>

Voici les 3 models qui sont associés :

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class UserHasPins < ActiveRecord::Base
  attr_accessible :users_id, :pins_id
  
 
  belongs_to :users_id
  belongs_to :pins_id
  
  
  validates :users_id, presence: true
  validates :pins_id, presence: true
end

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class User < ActiveRecord::Base


  has_many :pins_id, :through => :user_has_pin 
  has_many :user_has_pin
end

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class Pins < ActiveRecord::Base
  attr_accessible :content, :title
  
  
  has_many :users_id, :through => :user_has_pin
  has_many :user_has_pin

Si quelqu'un voit pourquoi j'ai cette exception ? =)

Merci par avance de vos réponses

[v.charlet]

Je suis pas fan du nomage de tes variables et par expérience (pour avoir galeré aussi) Ruby va utiliser les transformations singulier/pluriel pour retrouver le nom de la classe liée au has_many
d'ailleurs tu peux le forcer en utilisant la variable :class

Revenons à ton erreur: ton modele et tes relations ne sont pas correcte, commence par regler ça !

je ferai tellement de changement que je ne sais pas par ou commencer, les noms des classes au singulier, les belong_to au singulier et les has_many au pluriel
(et oui, c'est un maniac de la grammaire qui à créé ce langage)

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class UserHasPin < ActiveRecord::Base
 
  belongs_to :user
  belongs_to :pin

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class Pin < ActiveRecord::Base
  attr_accessible :content, :title
 
 
  has_many :users, :through => :user_has_pins, :source => :user
  has_many :user_has_pins

ajout de la :source pour aider ruby à determiner le sens de la relation

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class User < ActiveRecord::Base
 
 
  has_many :pins, :through => :user_has_pins, :source => :pin
  has_many :user_has_pins
end

j'ai pas testé mais j'ai un modele de base qui ressemble un peu ....

Tu peux facilement tester en utilisant la console rails, en creant un objet et en appellant la methode, cela doit te renvoyer [] puisque le lien n'existe pas, mais cela ne doit pas te planter
(attention à chaque modification du modele, il faut relancer la console pour prendre en compte les modifications

bon courage !

[v.charlet]

j'ai trouvé le temps de tester:

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$ rails generate model user
$ rails generate model pin
$ rails generate model userHasPin

je changerais aussi le nom de tes foreign keys

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class CreateUserHasPins < ActiveRecord::Migration
  def change
    create_table :user_has_pins do |t|
      t.integer :user_id
      t.integer :pin_id
 
      t.timestamps
    end
  end
end

mais ça marche beaucoup mieux

Code :

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$ rails c
Loading development environment (Rails 3.2.2)
irb(main):001:0> p1 = Pin.create(:title => "Pokemon")
  ←[1m←[36m (0.0ms)←[0m  ←[1mbegin transaction←[0m
  ←[1m←[35mSQL (37.0ms)←[0m  INSERT INTO "pins" ("created_at", "title", "updated_at") VALUES (?, ?, ?)  [["created_at", Fri, 27 Jul 2012 07:56:53 UTC +00:00], ["title", "Pokemon"], ["updated_at", Fri, 27 Jul 2012 0
7:56:53 UTC +00:00]]
  ←[1m←[36m (6.0ms)←[0m  ←[1mcommit transaction←[0m
=> #<Pin id: 1, title: "Pokemon", created_at: "2012-07-27 07:56:53", updated_at: "2012-07-27 07:56:53">
irb(main):002:0> p2 = Pin.create(:title => "Yugiho")
  &#8592;[1m&#8592;[35m (0.0ms)&#8592;[0m  begin transaction
  &#8592;[1m&#8592;[36mSQL (2.0ms)&#8592;[0m  &#8592;[1mINSERT INTO "pins" ("created_at", "title", "updated_at") VALUES (?, ?, ?)&#8592;[0m  [["created_at", Fri, 27 Jul 2012 07:57:06 UTC +00:00], ["title", "Yugiho"], ["updated_at", Fri, 27 Jul
2012 07:57:06 UTC +00:00]]
  &#8592;[1m&#8592;[35m (8.0ms)&#8592;[0m  commit transaction
=> #<Pin id: 2, title: "Yugiho", created_at: "2012-07-27 07:57:06", updated_at: "2012-07-27 07:57:06">
irb(main):003:0> u = User.create()
  &#8592;[1m&#8592;[36m (0.0ms)&#8592;[0m  &#8592;[1mbegin transaction&#8592;[0m
  &#8592;[1m&#8592;[35mSQL (2.0ms)&#8592;[0m  INSERT INTO "users" ("created_at", "updated_at") VALUES (?, ?)  [["created_at", Fri, 27 Jul 2012 07:57:18 UTC +00:00], ["updated_at", Fri, 27 Jul 2012 07:57:18 UTC +00:00]]
  &#8592;[1m&#8592;[36m (5.0ms)&#8592;[0m  &#8592;[1mcommit transaction&#8592;[0m
=> #<User id: 1, created_at: "2012-07-27 07:57:18", updated_at: "2012-07-27 07:57:18">
irb(main):004:0> u.user_has_pins.create(:pin_id => 1)
  &#8592;[1m&#8592;[35m (0.0ms)&#8592;[0m  begin transaction
  &#8592;[1m&#8592;[36mSQL (1.0ms)&#8592;[0m  &#8592;[1mINSERT INTO "user_has_pins" ("created_at", "pin_id", "updated_at", "user_id") VALUES (?, ?, ?, ?)&#8592;[0m  [["created_at", Fri, 27 Jul 2012 07:57:58 UTC +00:00], ["pin_id", 1], ["updated_at", Fri, 27 Jul 2012 07:57:58 UTC +00:00], ["user_id", 1]]
  &#8592;[1m&#8592;[35m (4.0ms)&#8592;[0m  commit transaction
=> #<UserHasPin id: 1, user_id: 1, pin_id: 1, created_at: "2012-07-27 07:57:58", updated_at: "2012-07-27 07:57:58">
irb(main):005:0> u.pins
  &#8592;[1m&#8592;[36mPin Load (0.0ms)&#8592;[0m  &#8592;[1mSELECT "pins".* FROM "pins" INNER JOIN "user_has_pins" ON "pins"."id" = "user_has_pins"."pin_id" WHERE "user_has_pins"."user_id" = 1&#8592;[0m
=> [#<Pin id: 1, title: "Pokemon", created_at: "2012-07-27 07:56:53", updated_at: "2012-07-27 07:56:53">]
irb(main):006:0> p1.users
  &#8592;[1m&#8592;[35mUser Load (1.0ms)&#8592;[0m  SELECT "users".* FROM "users" INNER JOIN "user_has_pins" ON "users"."id" = "user_has_pins"."user_id" WHERE "user_has_pins"."pin_id" = 1
=> [#<User id: 1, created_at: "2012-07-27 07:57:18", updated_at: "2012-07-27 07:57:18">]
irb(main):007:0> p2.users
  &#8592;[1m&#8592;[36mUser Load (1.0ms)&#8592;[0m  &#8592;[1mSELECT "users".* FROM "users" INNER JOIN "user_has_pins" ON "users"."id" = "user_has_pins"."user_id" WHERE "user_has_pins"."pin_id" = 2&#8592;[0m
=> []