多对多关联外键更改集错误

为了 has_* 我们有 no_assoc_constraint . 当我们试图删除父级而子级仍然存在时,它工作正常并抛出一个变更集错误。有什么功能可以使用吗 many to many .

就像这三种模式

   schema "facilities" do         
    field(:name, :string)
    field(:description, :string)
    field(:is_active, :boolean, default: true)


    many_to_many(:users, User, join_through: "users_facilities")
  end

   schema "users_facilities" do
    belongs_to(:user, User, primary_key: true)
    belongs_to(:facility, Facility, primary_key: true)
   end

   schema "users" do
    field(:first_name, :string)
    field(:last_name, :string)
    field(:email_address, :string)
    field(:username, :string)
    many_to_many(:facilities, Facility, join_through: 
   "users_facilities")

当我试图删除一个设施时,其外键存在于用户设施中。我想得到变更集错误。