ruby-on-rails - 删除父项时，Rails将子项关联ID设置为nil(Rails Set child association id to nil when deleting parent)

Question

This is my association set up between my Collection and Album models:

(这是我的Collection夹和Album模型之间建立的关联：)

class Collection < ActiveRecord::Base
  has_many :children, class_name: "Collection", foreign_key: "parent_id"
  belongs_to :parent, class_name: "Collection", foreign_key: "parent_id", optional: true
  has_many :albums
end

---

class Album < ActiveRecord::Base
  has_many :photos, dependent: :destroy
  belongs_to :collection, optional: true
end

I've just deleted all the Collection 's, and I expected the collection_id of each Album to be returned to NULL as the parent no longer exists.

(我刚刚删除了所有Collection ，并且我希望每个Album的collection_id都将返回NULL因为父级不再存在。)

How can I make sure this happens when an Album 's parent Collection is deleted?

(如何删除Album的父Collection Album时发生这种情况？)

  ask by rctneil translate from so

Answer 1

使用dependent: nullify在您的Collection dependent: nullify模型中dependent: nullify ：

has_many :albums, dependent: :nullify