Question

我对mongoid完全陌生。是否有类关系定义中的任何选项或内容来启用此功能？

class Band
  include Mongoid::Document
  field :name, type:String
  has_and_belongs_to_many :members
end

class Member
  include Mongoid::Document
  field :name, type: String
  has_and_belongs_to_many :bands
end

andy = Member.new(name: 'Andy Bell')

ride = Band.new(name: 'Ride')
ride.members << andy
oasis = Band.new(name: 'Oasis')
oasis.members << andy

andy.bands #=> returns: [] (empty array)
andy.band_ids #=> returns: [BSON::ObjectId('53586a786d6163870c030000'), BSON::ObjectId('53586a786d6163870c040000')]

Answer 1

我不确定但是从the docs here读取有重新加载方法，这有帮助吗？：

如果您在作为关系一部分的模型上使用默认范围你必须像has_many，has_and_belongs_to_many或embeds_many一样重新加载关系以重新应用范围。这很重要请注意，如果您在关系中更改文档的值影响其在范围关系中的可见性。

class Label
  include Mongoid::Document
  embeds_many :bands
end

class Band
  include Mongoid::Document
  field :active, default: true
  embedded_in :label
  default_scoped where(active: true)
end

label.bands.push(band)
label.bands #=> [ band ]
band.update_attribute(:active, false)
label.bands #=> [ band ] Must reload.
label.reload.bands #=> []

Mongoid：如何在N对N关系中引用子对象的父对象属性

1 个答案: