Rails:获取下一个/上一个记录 [英] Rails: Get next / previous record

问题描述

我的应用有属于用户的照片.

My app has Photos that belong to Users.

在 photo#show 视图中，我想显示来自该用户的更多信息"，并显示来自该用户的下一张和上一张照片.如果这些是 id 顺序中的下一张/上一张照片或 created_at 顺序中的下一张/上一张照片，我会很好.

In a photo#show view I'd like to show "More from this user", and show a next and previous photo from that user. I would be fine with these being the next/previous photo in id order or the next/previous photo in created_at order.

您将如何为下一张/上一张照片或多张下一张/上一张照片编写这种查询?

How would you write that kind of query for one next / previous photo, or for multiple next / previous photos?

推荐答案

试试这个:

class User
  has_many :photos
end


class Photo
  belongs_to :user

  def next
    user.photos.where("id > ?", id).first
  end

  def prev
    user.photos.where("id < ?", id).last
  end

end

现在您可以:

photo.next
photo.prev

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