ruby-on-rails - Rails 4でカスタム文字列外部キーを設定するには?

Question

文字列foreign_keyを使用してhas_oneを適切に設定するための関連付けを設定するにはどうすればよいですか?

class Pharmaceutic < ActiveRecord::Base
  has_one :pharmaceutic_group, foreign_key: "code"
end

class PharmaceuticGroup < ActiveRecord::Base
  belongs_to :pharmaceutic, primary_key: 'code'
end

>> Pharmaceutic.last.pharmaceutic_group                                                                                        
  Pharmaceutic Load (0.3ms)  SELECT `pharmaceutics`.* FROM `pharmaceutics` ORDER BY `pharmaceutics`.`id` DESC LIMIT 1
  PharmaceuticGroup Load (0.3ms)  SELECT `pharmaceutic_groups`.* FROM `pharmaceutic_groups` WHERE `pharmaceutic_groups`.`code` = 2 ORDER BY `pharmaceutic_groups`.`id` ASC LIMIT 1
=> nil
>> Pharmaceutic
=> Pharmaceutic(id: integer, package_type: integer, group_code: string)
>> PharmaceuticGroup
=> PharmaceuticGroup(id: integer, code: string, name: string)

例えば: Pharmaceutic には group_code: がaaaあり、PharmaceuticGroup には code: がありますaaa。Pharmaceutic.last.pharmaceutic_group.name => 'AAA group name'

Answer 1

次のようPharmaceutic belongs_to :pharmaceutic_groupに andを使用する必要があると思います。PharmaceuticGroup has_many :pharmaceutics

class Pharmaceutic < ActiveRecord::Base
  belongs_to :pharmaceutic_group, foreign_key: :group_code, primary_key: :code
end

class PharmaceuticGroup < ActiveRecord::Base
  has_many :pharmaceutics, foreign_key: :group_code, primary_key: :code
end