ruby-on-rails - rails :dependent=>:destroy 被忽略

Question

我的关联选项似乎没有得到兑现。

class ClassRoom < ActiveRecord::Base
  has_many :class_assignments, :dependent => :destroy
  has_many :people, :through=>:class_assignments

class Person < ActiveRecord::Base
  has_many :class_assignments, :dependent => :destroy
  has_many :class_rooms, :through=>:class_assignments

class ClassAssignment < ActiveRecord::Base
  belongs_to :person
  belongs_to :class_room

也就是说，当一个人或一个教室被删除时，连接表/模型中的记录也应该被删除。

但是，ClassRoom.last.destroy破坏了ClassRoom，但没有任何关联的ClassAssignments。

我知道在使用:dependent=>:destroy时会被忽略:through，但我应该可以在连接模型上使用它吧？

Answer 1

尝试

  class ClassRoom < ActiveRecord::Base 
  def before_destroy
    self.class_assignments.destroy_all
  end

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