Mongoid只使用created_at时间戳

Question

有没有办法只为只读文档设置created_at时间戳？

目前，我有以下消息类

class Message 
    include Mongoid::Document 
    include Mongoid::Timestamps 

    field :text,  type: String 

    belongs_to :user, foreign_key: :user_id 
    embedded_in :conversation 
end 

它工作正常，但对于每封邮件，我用的updated_at领域浪费空间，这将永远是相同的created_at

Answer 1

通过此页面的时间戳部分。 https://docs.mongodb.com/mongoid/master/tutorials/mongoid-documents/

include Mongoid::Timestamps    - created_at and updated_at. 
include Mongoid::Timestamps::Created - created_at only. 
include Mongoid::Timestamps::Updated - updated_at only. 

ü甚至可以短名称

include Mongoid::Timestamps::Short   - c_at and u_at. 
include Mongoid::Timestamps::Created::Short - c_at only. 
include Mongoid::Timestamps::Updated::Short - u_at only. 

Answer 2

包括Mongoid::Timestamps::Created而不是Mongoid::Timestamps。

class Message 
    include Mongoid::Document 
    include Mongoid::Timestamps::Created 

    field :text,  type: String 

    belongs_to :user, foreign_key: :user_id 
    embedded_in :conversation 
end