我如何反思一个ActiveRecord对象，以确定其是否新的或产生的？

How can I introspect an ActiveRecord object to determine whether its new or created?

推荐答案

问对象，如果它是一个新的记录

ask the object if it's a new record

 object.new_record?

http://apidock.com/rails/ActiveRecord/Persistence/new_record%3F