Rails HABTM has_many 破坏错误答案

【问题标题】：Rails HABTM has_many destroy errorRails HABTM has_many 破坏错误
【发布时间】：2017-08-18 00:01:20
【问题描述】：

我有一个has_and_belongs_to_many 在用户和工作区之间使用has_many。

user.rb

class User < ActiveRecord::Base
  has_many :user_workspaces, dependent: :destroy
  has_many :workspaces, through: :user_workspaces 
  before_destroy :delete_workspaces

 def delete_workspaces
   self.workspaces.each(&:destroy)
 end

workspace.rb

class Workspace < ActiveRecord::Base
  has_many    :user_workspaces
  has_many    :users, through :user_workspaces
end

user_workspaces 类和迁移：

class UserWorkspace < ActiveRecord::Base 
  self.table_name  = "user_workspaces"
  belongs_to  :user 
  belongs_to  :workspace
end

class CreateUsersAndWorkspaces < ActiveRecord::Migration
  def change
    create_table :users_workspaces, id: false do |t|
      t.belongs_to :user, index: true
      t.belongs_to :workspace, index: true
      t.boolean :admin, default: true  
    end
  end
end
    class RenameUsersWorkspaces < ActiveRecord::Migration
  def change
    rename_table('users_workspaces', 'user_workspaces')
  end
end

我希望这两个测试都通过：

should "destroy all associatios and objects" do 
  user = User.create!(attributes_for(:user))
  w = user.workspaces.create!(attributes_for(:workspace))
  user.destroy 
  assert UserWorkspace.all.empty? #asser there are no associations
end

这给了我错误

ActiveRecord::StatementInvalid: SQLite3::SQLException: 没有这样的列： user_workspaces.：从“user_workspaces”中删除 "user_workspaces"."" = ?

 should "destroy association when destroying workspace" do
      user = User.create!(attributes_for(:user))
      w = user.workspaces.create!(attributes_for(:workspace))
      w.destroy
      assert UserWorkspace.all.empty?
 end

我怎样才能涵盖这两种情况？销毁用户会销毁关联和工作区，销毁工作区也会销毁关联

【问题讨论】：

标签： ruby-on-rails has-many-through has-and-belongs-to-many minitest

【解决方案1】：

根据http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html只需要忽略连接表即可。

Workspace.rb 现在有依赖销毁，仅销毁连接（销毁的预期行为）

  has_many    :users,             through:      :user_workspaces,
                                  inverse_of:   :workspaces,
                                  dependent:    :destroy

然后 user.rb 保留 delete_workspaces 函数，但添加dependent: :destroy 以同时销毁关联。

用户.rb

    before_destroy: :delete_workspaces
    has_many :workspaces,           through: :user_workspaces,                                   
                                     dependent: :destroy

 def delete_workspaces
   self.workspaces.each(&:destroy)
 end

现在两个测试都通过了。

【讨论】：