Question

假设我有一个模型用户has_many Post children。

显然我可以使用以下内容访问孩子：

user = User.first
posts = user.posts

但是我怎样才能将这些帖子削减到那些符合某些条件的帖子？

user = User.first
posts = user.posts
recent_posts = posts.where(:created_at => > (Time.now - 1.day))

我正在使用Rails 2.3.11

Answer 1

试试这个：

class User
  has_many :posts do
    def recent duration=1.day
      all(:conditions => ["created_at >= ? ", duration.ago])
    end
  end

end

现在您可以进行以下调用：

user.posts # all posts for user
user.posts.recent # posts since last one day
user.posts.recent(2.days) # posts since last two days
user.posts.recent(30.minutes) # posts since last 30 minutes

Answer 2

Rails 2：

recent_posts = posts.all(:conditions=> ['created_at > ?', (Time.now - 1.day)])

Rails 3：

recent_posts = posts.where('created_at > ?', (Time.now - 1.day))

在Rails中只选择某些模型的子项

2 个答案: