next_played_videos = @channel.videos.active.where(:begin_time.gt => begin_time).asc(:begin_time) next_played_videos.each do |video| video.begin_time = begin_time video.end_time = video.begin_time.to_i + video.duration begin_time = video.end_time video.save end
这里使用 each 操作遍历效率比较低，可以使用 Mongoid 的 inc 方法批量对指定的字段值进行增减，文档见 http://mongoid.org/en/mongoid/docs/persistence.html。
next_played_videos = @channel.videos.active.where(:begin_time.gt => begin_time).asc(:begin_time)
next_played_videos.inc(begin_at: -@video.duration, end_at: -@video.duration)
原文：http://www.cnblogs.com/iwangzheng/p/4685540.html