Question

我正在使用rails 4.1.12并最近尝试创建has_many_through关联。

我的榜样

# == Schema Information
#
# Table name: roles
#
#  id         :integer          not null, primary key
#  name       :string(255)
#  created_at :datetime
#  updated_at :datetime
#

class Role < ActiveRecord::Base

  has_many :users
  
  has_many :roles_responsibilities
  has_many :responsibilities, through: :roles_responsibilities

end

责任模型

# == Schema Information
#
# Table name: responsibilities
#
#  id              :integer          not null, primary key
#  action_name     :string(255)
#  controller_name :string(255)
#  created_at      :datetime
#  updated_at      :datetime
#

class Responsibility < ActiveRecord::Base
  
  has_many :roles_responsibilities
  has_many :roles, through: :roles_responsibilities

end

和

Roles_responsibilities

# == Schema Information
#
# Table name: roles_responsibilities
#
#  id                :integer          not null, primary key
#  role_id           :integer
#  responsibility_id :integer
#  user_id           :integer
#  user_type         :string(255)
#  created_at        :datetime
#  updated_at        :datetime
#

class RolesResponsibility < ActiveRecord::Base
belongs_to :role
belongs_to :responsibility
end

我相信我做得不对，但得到了一个奇怪的

 NameError: undefined local variable or method `  ' for Role (call 'Role.connection' to establish a connection):Class

在模特中。

我检查了所有拼写和语法，但不确定为什么我收到此错误？

任何人都可以帮我找到错误吗？

Answer 1

这是因为ActiveRecord为您的数据库连接延迟加载。如果再次运行查询，它应该可以正常工作，根据this SO问题。您可以通过运行Role.count

之类的内容来仔细检查

奇怪的rails4.1 has_many_through关联bug

1 个答案: