如何從Rails中的對象獲取創建日期？

Question

您好，我在Rails中有一個應用程序，我需要從一個對象中檢索創建日期。 我知道Rails使用時間戳自動保存此信息，並且我查看了具有Created_at信息的.json螞蟻。 問題是如何從對象訪問此信息（Created_at）（我的意圖是按創建時間排序，並顯示此信息）

謝謝你的幫助

Answer 1

您可以通過以下方式訪問該屬性：

u = User.first   # Let's pretend there's a `User` model within the rails application. Here im getting the first record and storing that user in the variable `u`.

u[:created_at]  # This will give me the value for the `created_at`, for instance: Thu, 18 Oct 2012 14:42:44 UTC +00:00 

or

u.created_at  # will give you the same result

如果sort該字段sort ，可以（例如假設有一個User模型）使用sort_by ：

User.all.sort_by &:created_at  # This is just a demonstration, you might want to get a sub-set of whatever model you're querying with `where` and some relevant criteria.

要么

   User.find(:all, :order => "created_at")  # old and deprecated approach

要么

   User.order("created_at DESC") #  more recent approach