Question

我无法通过关联验证has_many中的模型。以下是相关模型：

广播模式

class Broadcast < ActiveRecord::Base

    attr_accessible :content,
                    :expires,
                    :user_ids,
                    :user_id

    has_many :users, through: :broadcast_receipts
    has_many :broadcast_receipts, dependent: :destroy

    validates :user_id, presence: true
    validates :content, presence: true

end

广播收据模型

class BroadcastReceipt < ActiveRecord::Base

    belongs_to :broadcast
    belongs_to :user

    attr_accessible :user_id, :cleared, :broadcast_id

    validates :user_id      , presence: true
    validates :broadcast_id         , presence: true
end

还有一个与用户有关联，通过广播收据广播收据。

问题似乎在以下一行：

validates :broadcast_id         , presence: true

每当我尝试创建一个Broadcast时，我都会收到一个没有给出错误消息的回滚。但是，删除上面的行时，一切都按预期工作。

这看起来像是在创建广播收据之前未保存广播的问题有什么方法可以验证在收据模型上设置的broadcast_id吗？

Answer 1

这似乎与此处讨论的问题相同：https://github.com/rails/rails/issues/8828，通过添加：与连接模型的has_many关联的反转来解决。

Answer 2

您的代码结构可能存在一些问题。你可以尝试这个版本。

class Broadcast < ActiveRecord::Base
  # I assume these are the recipients
  has_many :broadcast_receipts, dependent: :destroy
  has_many :users, through: :broadcast_receipts

  # I assume this is the creator
  validates :user_id, :content, presence: true
  attr_accessible :content, :expires, :user_id, :user_ids
end

class BroadcastReceipt < ActiveRecord::Base
  belongs_to :broadcast
  belongs_to :user

  # You should be able to validate the presence
  # of an associated model directly
  validates :user, :broadcast, presence: true

  attr_accessible :cleared
end

Rails has_many：通过验证

2 个答案: