Question

我有一个Users类和一个UserGroup类：

class User < ActiveRecord::Base
  has_many :group_memberships
  has_many :users_groups, through: :group_memberships

  ...

class UsersGroup < ActiveRecord::Base
  has_many :group_memberships
  has_many :users, through: :group_memberships

...和一个加入他们的GroupMembership类 -

class GroupMembership < ActiveRecord::Base
  belongs_to :users, dependent: :destroy
  belongs_to :users_groups, dependent: :destroy

我的迁移看起来像这样 -

class CreateUsersGroups < ActiveRecord::Migration
  def change
    create_table :users_groups do |t|
     t.string :title
     t.string :status
     t.string :about

     t.timestamps null: false
    end
  end
end

class CreateGroupMembership < ActiveRecord::Migration
  def change
    create_table :group_memberships do |t|
      t.integer :user_id, index: true
      t.integer :users_group_id, index: true
      t.boolean :owner
    end
  end
end

所以user.group_memberships非常高兴，但user.users_groups会返回错误 -

undefined method `relation_delegate_class' for Users:Module

同样，users_group.group_memberships很好，但users_group.users会返回完全相同的错误 -

undefined method `relation_delegate_class' for Users:Module

...在用户模块上。我已经盯着这看了几个小时，但我确定它的语法很简单。有什么问题？

Answer 1

使用belongs_to时我相信你需要使用单数格式：所以不是belongs_to :users而是belongs_to :user

class GroupMembership < ActiveRecord::Base
  belongs_to :user, dependent: :destroy
  belongs_to :writers_group, dependent: :destroy

Answer 2

我相信，因为你正在使用＆＃39;通过＆＃39;你将不得不使用：

user.group_memberships.users_groups

这是因为用户没有users_groups，反之亦然。

而是通过group_memberships访问users_groups。

has_many，through - undefined method`conlation_delegate_class'

2 个答案: