Question

我正在使用redis和Rails为我的webapp创建一个点击计数器。

我在Redis中保存视图，然后每天更新数据库中的值。

要增加视图，我使用此方法：

  def self.async_increase_visits
    $redis.hkeys('video_visits').each do |id|
      self.find(id).increase_visit($redis.hget('video_visits', id))
      $redis.hdel('video_visits', id)
    end
  end

  def increase_visit(visits)
    self.increment!(:impressions_count, visits.to_i)
  end

我注意到生成的查询是：

Loading staging environment (Rails 4.0.0)
2.0.0-p353 :001 > Content.async_increase_visits
  Content Load (5.1ms)  SELECT "contents".* FROM "contents" WHERE "contents"."id" = $1 ORDER BY published_at DESC LIMIT 1  [["id", "12300"]]
   (0.3ms)  BEGIN
  ContentElement Load (7.8ms)  SELECT "content_elements".* FROM "content_elements" WHERE "content_elements"."content_id" = $1 ORDER BY "content_elements".position ASC  [["content_id", 12300]]
  SQL (15.7ms)  UPDATE "contents" SET "impressions_count" = $1, "updated_at" = $2 WHERE "contents"."type" IN ('News') AND "contents"."id" = 12300  [["impressions_count", 3], ["updated_at", Fri, 02 May 2014 18:58:30 CEST +02:00]]
  SQL (15.5ms)  UPDATE "comments" SET "commentable_state" = 'published', "commentable_url" = '#' WHERE "comments"."id" IN (SELECT "comments"."id" FROM "comments" WHERE "comments"."commentable_id" = $1 AND "comments"."commentable_type" = $2 ORDER BY comments.created_at asc)  [["commentable_id", 12300], ["commentable_type", "Content"]]
   (1.7ms)  COMMIT
 => ["12300"]
2.0.0-p353 :002 > Content.async_increase_visits
  Content Load (1.1ms)  SELECT "contents".* FROM "contents" WHERE "contents"."id" = $1 ORDER BY published_at DESC LIMIT 1  [["id", "12448"]]
   (0.2ms)  BEGIN
  ContentElement Load (0.8ms)  SELECT "content_elements".* FROM "content_elements" WHERE "content_elements"."content_id" = $1 ORDER BY "content_elements".position ASC  [["content_id", 12448]]
  SQL (2.9ms)  UPDATE "contents" SET "impressions_count" = $1, "updated_at" = $2 WHERE "contents"."type" IN ('News') AND "contents"."id" = 12448  [["impressions_count", 2], ["updated_at", Fri, 02 May 2014 18:59:10 CEST +02:00]]
  SQL (4.7ms)  UPDATE "comments" SET "commentable_state" = 'published', "commentable_url" = '#' WHERE "comments"."id" IN (SELECT "comments"."id" FROM "comments" WHERE "comments"."commentable_id" = $1 AND "comments"."commentable_type" = $2 ORDER BY comments.created_at asc)  [["commentable_id", 12448], ["commentable_type", "Content"]]
   (1.2ms)  COMMIT
 => ["12448"]

我的内容有很多评论（多元关联），但我不明白为什么要简单的＆＃34;增量＆＃34;我也在协会中更新了一些价值。

如何仅更新impressions_count值？

Answer 1

increment!方法调用回调。如果您只需更新此列以跳过回调和验证，则可以使用update_counters方法。

http://api.rubyonrails.org/classes/ActiveRecord/CounterCache/ClassMethods.html#method-i-update_counters

def increase_visit(visits)
  Content.update_counters(self.id, impressions_count: visits.to_i)
end

Activerecord增量！更新协会，为什么？

1 个答案: