ruby on rails before_save 增加表的不同列

Question

这是我的 like.rb 模型

class Like < ActiveRecord::Base
  attr_accessible :user_id, :post_id

  before_save :increment_post_total_likes

  before_destroy :decrement_post_total_likes

  scope :desc_ordered, :order => "created_at DESC"

  belongs_to :post
  belongs_to :user

  def increment_post_total_likes
    p = Post.find(self.post_id)
    p.increment!(:total_likes)
    p.save
  end

  def decrement_post_total_likes
    p = Post.find(self.post_id)
    p.decrement!(:total_likes)
    p.save
  end

  def self.alreadyLiked(post_id, user_id)
    where(:user_id => user_id, :post_id => post_id).any?
  end

  def self.already_liked?(user_id)
    exists?(:user_id => user_id)
  end

end

问题是，当我喜欢一个帖子时，它会增加帖子total_likes 列，但也会增加另一个表列，这两个列共享相关列，如post_id 和user_id，我不明白为什么。 ..

我只想在 likes 表上使用 before_save 和 before_destroy

Answer 1

increment! 将 save the record for you。尝试一下，不要爆炸。