使用Ruby-on-Rails，我想存储一个由3个元素组成的数组:帖子的最后3条 comments .我知道我可以将 comments 表加入到帖子1中，但是为了zoom 的目的，我会避免做这个繁重的请求.
So I was wondering what was the best way to store those 3 elements, as I would like to update them easily every time a new comment is made: remove the last comment and add the new one.
What is the correct way to do this ? Store it in a serialized array or in a JSON object ?
您可以使用ActiveRecord的serialize声明存储数组和散列:
class Comment < ActiveRecord::Base
serialize :stuff
end
comment = Comment.new # stuff: nil
comment.stuff = ['some', 'stuff', 'as array']
comment.save
comment.stuff # => ['some', 'stuff', 'as array']
您可以指定对象类型应等于的类名(在本例中为Array).这更明确，也更安全.在分配第一个值时，您也不必创建数组，因为您可以将其追加到现有(空)数组中.
class Comment < ActiveRecord::Base
serialize :stuff, Array
end
comment = Comment.new # stuff: []
comment.stuff << 'some' << 'stuff' << 'as array'
你甚至可以使用一个更整洁的版本，名为store:http://api.rubyonrails.org/classes/ActiveRecord/Store.html
This should handle your use case using a built in method.