Question

我在轨道3.2.14上有ruby的项目。我有2个名为“countries”和“users”的表。在“users”表中，FK名为“countries_id”。在模型上我有表关系，如：在countries.rb我设置了关系：

class Countries < ActiveRecord::Base
  self.primary_key = "id"
  has_many  :users,  :dependent => :destroy # plural
end

，在users.rb中，如：

class Users < ActiveRecord::Base
  self.primary_key = "id"


  belongs_to    :countries,
                :class_name => "Countries",
                :foreign_key => "countries_id"

end

当我想检查复数关系时，它没有.. 我输入rails console命令，如下所示

c=Countries.find_by_id(1)

然后当我输入命令u=c.users时，我有一些错误错误：

c=Countries.find_by_id(1)
  Countries Load (0.3ms)  SELECT `countries`.* FROM `countries` WHERE `countries`.`id` = 1 LIMIT 1
 => #<Countries id: 1, code: "IND", name: "Indonesia", created_at: "2014-02-17 09:18:11", updated_at: "2014-02-17 09:18:11"> 
1.9.3-p484 :012 > u=c.users
NameError: uninitialized constant Countries::User
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/activerecord-3.2.14/lib/active_record/inheritance.rb:111:in `compute_type'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/activerecord-3.2.14/lib/active_record/reflection.rb:172:in `klass'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/activerecord-3.2.14/lib/active_record/associations/association.rb:118:in `klass'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/activerecord-3.2.14/lib/active_record/associations/association.rb:171:in `find_target?'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/activerecord-3.2.14/lib/active_record/associations/collection_association.rb:334:in `load_target'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/activerecord-3.2.14/lib/active_record/associations/collection_proxy.rb:44:in `load_target'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/activerecord-3.2.14/lib/active_record/associations/collection_proxy.rb:87:in `method_missing'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/railties-3.2.14/lib/rails/commands/console.rb:47:in `start'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/railties-3.2.14/lib/rails/commands/console.rb:8:in `start'
    from /home/vinra/.rvm/gems/ruby-1.9.3-p484@rails3.2/gems/railties-3.2.14/lib/rails/commands.rb:41:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'
1.9.3-p484 :013 > ^C
1.9.3-p484 :013 >

我知道我的问题真的让人跳了起来无论如何，谢谢你，抱歉我的英语不好：）

Answer 1

您应该在代码中更改很多内容：

应用/模型/ country.rb

class Country < ActiveRecord::Base has_many :users, :dependent => :destroy end

应用/模型/ user.rb

class Users < ActiveRecord::Base belongs_to :country, :foreign_key => "countries_id" end

并像这样使用它：

country = Country.find(1) p country.users

Answer 2

问题是Rails Active Record模型不能多个。您创建了具有复数的模型，因此将它们更改为单数或更好的方法是使用单数名称再次创建它们。

Countries应为Country，Users应为User。

有关命名约定的详细信息，请参阅This。

希望它有所帮助！

检查模型上的关系表，轨道上的红宝石

2 个答案: