小编Nat*_*erg的帖子

我想在我正在构建的应用程序中使用UUID并遇到一些问题.由于UUID(v4)不是可排序的,因为它们是随机生成的,我试图首先覆盖ActiveRecord :: Base#,但Rails对此并不太满意.它对我大吼我说如果我想排序并正确排序,ArgumentError: You tried to define a scope named "first" on the model "Item", but Active Record already defined a class method with the same name.我是否必须使用不同的方法？

这是酱:

# lib/sortable_uuid.rb
module SortableUUID
  def self.included(base)
    base.class_eval do
      scope :first, -> { order("created_at").first }
      scope :last, -> { order("created_at DESC").first }
    end
  end
end


# app/models/item.rb
class Item < ActiveRecord::Base
  include SortableUUID
end

Rails 4.2,Ruby 2.2.2

参考:

• http://blog.nakonieczny.it/posts/rails-support-for-uuid/
• http://linhmtran168.github.io/blog/2014/03/17/postgres-uuid-in-rails/(缺点部分)