1

正如您在下面的当前代码中看到的那样，我正在根据属性 recordable_id 找到重复项。我需要做的是根据四个匹配属性找到重复项：user_id、recordable_type、hero_type、recordable_id。我必须如何修改代码？

heroes = User.heroes

for hero in heroes
  hero_statuses = hero.hero_statuses

  seen = []

  hero_statuses.sort! {|a,b| a.created_at <=> b.created_at } # sort by created_at
  hero_statuses.each do |hero_status|
    if seen.map(&:recordable_id).include? hero_status.recordable_id # check if the id has been seen already
      hero_status.revoke
    else
      seen << hero_status # if not, add it to the seen array
    end
  end
end
4

2 回答 2

1

尝试这个：

HeroStatus.all(:group =>  "user_id, recordable_type, hero_type, recordable_id",
               :having => "count(*) > 1").each do |status|
  status.revoke 
end

编辑 2 要撤销所有最新的重复条目，请执行以下操作：

HeroStatus.all(:joins => "(
     SELECT   user_id, recordable_type, hero_type, 
              recordable_id, MIN(created_at) AS created_at
     FROM     hero_statuses
     GROUP BY user_id, recordable_type, hero_type, recordable_id
     HAVING   COUNT(*) > 1
   ) AS A ON A.user_id         = hero_statuses.user_id         AND 
             A.recordable_type = hero_statuses.recordable_type AND
             A.hero_type       = hero_statuses.hero_type       AND
             A.recordable_id   = hero_statuses.recordable_id   AND
             A.created_at      < hero_statuses.created_
").each do |status|
  status.revoke 
end
于 2010-05-08T00:30:37.270 回答
0

使用直接 Ruby（不是 SQL 服务器）：

heroes = User.heroes

for hero in heroes
  hero_statuses = hero.hero_statuses

  seen = {}

  hero_statuses.sort_by!(&:created_at)
  hero_statuses.each do |status|
    key = [status.user_id, status.recordable_type, status.hero_type, status.recordable_id]
    if seen.has_key?(key)
      status.revoke
    else
      seen[key] = status # if not, add it to the seen array
    end
  end

  remaining = seen.values
end

对于查找，请始终使用Hash（或Set，但在这里我认为保留已保留的状态会很好）

注意：我使用sort_by!了 ，但这是 1.9.2 的新功能，所以使用sort_by(或require "backports")

于 2010-05-08T05:11:20.267 回答