ruby-on-rails - 将计数器缓存添加到 rails 中的自连接表

我正在尝试在自联接关联中的列上添加计数器缓存。
我有两个模型用户和追随者。用户有来自用户表本身的关注者和被关注者。

User.rb

  has_many :followings
  has_many :followers, :through => :followings
  has_many :followees, :through => :followings

Following.rb

class Following < ActiveRecord::Base
  attr_accessible :followee_id, :follower_id
  belongs_to :follower, :class_name => "User"
  belongs_to :followee, :class_name => "User"
end

现在我想在 follower 和 followees 上添加计数器缓存。我在 followers_count 表中有 followees_count 和 user 列。

我试过了

belongs_to :follower, :class_name => "User" , :counter_cache => true

但这不会返回用户表中的任何数据。
任何帮助，将不胜感激。

最佳答案

这是很久以前的事了，但是

用户.rb

class User < ActiveRecord::Base
  has_many :followings_as_follower, class_name: 'Following', foreign_key: 'follower_id', dependent: :destroy
  has_many :followings_as_followee, class_name: 'Following', foreign_key: 'followee_id', dependent: :destroy
  has_many :followers, through: :followings_as_followee, source: :follower
  has_many :followees, through: :followings_as_follower,  source: :followee

  def follow?(user)
    followees.reload.include? user
  end

  def follow(user)
    return if follow?(user)
    followings_as_follower.create(followee: user)
  end

  def unfollow(user)
    return unless follow?(user)
    followings_as_follower.where(followee: user).first.destroy
  end
end

Follow.rb

class Following < ActiveRecord::Base
  belongs_to :follower, class_name: 'User', counter_cache: :followees_count
  belongs_to :followee, class_name: 'User', counter_cache: :followers_count
  validates :follower, presence: true
  validates :followee, presence: true
  validates :followee, uniqueness: { scope: [:follower, :followee] }
end

关于ruby-on-rails - 将计数器缓存添加到 rails 中的自连接表，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/15133545/