ruby-on-rails - inverse_of - rails references

has_many: a través de una clave externa?

Question

He leído varias preguntas sobre esto, pero todavía tengo que encontrar una respuesta que funcione para mi situación.

Tengo 3 modelos: Apps , AppsGenres y Genres

Aquí están los campos pertinentes de cada uno de esos:

Apps
application_id

AppsGenres
genre_id
application_id

Genres
genre_id

La clave aquí es que no estoy usando el campo de id de esos modelos.

Necesito asociar las tablas basadas en esos campos application_id y genre_id .

Esto es lo que tengo actualmente, pero no me está dando la consulta que necesito:

class Genre < ActiveRecord::Base
  has_many :apps_genres, :primary_key => :application_id, :foreign_key => :application_id
  has_many :apps, :through => :apps_genres
end

class AppsGenre < ActiveRecord::Base
  belongs_to :app, :foreign_key => :application_id
  belongs_to :genre, :foreign_key => :application_id, :primary_key => :application_id
end

class App < ActiveRecord::Base
  has_many :apps_genres, :foreign_key => :application_id, :primary_key => :application_id
  has_many :genres, :through => :apps_genres
end

Para referencia, aquí está la consulta que finalmente necesito:

@apps = Genre.find_by_genre_id(6000).apps

SELECT "apps".* FROM "apps" 
   INNER JOIN "apps_genres" 
      ON "apps"."application_id" = "apps_genres"."application_id" 
   WHERE "apps_genres"."genre_id" = 6000

Answer 1

ACTUALIZADO Prueba esto:

class App < ActiveRecord::Base
  has_many :apps_genres, :foreign_key => :application_id
  has_many :genres, :through => :apps_genres
end

class AppsGenre < ActiveRecord::Base
  belongs_to :genre, :foreign_key => :genre_id, :primary_key => :genre_id
  belongs_to :app, :foreign_key => :application_id, :primary_key => :application_id
end

class Genre < ActiveRecord::Base
  has_many :apps_genres, :foreign_key => :genre_id
  has_many :apps, :through => :apps_genres
end

Con consulta:

App.find(1).genres

Genera:

SELECT `genres`.* FROM `genres` INNER JOIN `apps_genres` ON `genres`.`genre_id` = `apps_genres`.`genre_id` WHERE `apps_genres`.`application_id` = 1

Y consulta:

Genre.find(1).apps

genera:

SELECT `apps`.* FROM `apps` INNER JOIN `apps_genres` ON `apps`.`application_id` = `apps_genres`.`application_id` WHERE `apps_genres`.`genre_id` = 1