ruby-on-rails – 在rails中为自联接表添加计数器缓存

发布时间：2020-12-17 02:38:10 所属栏目：百科来源：网络整理

导读：我试图在自联接关联中的列上添加计数器缓存. 我有两个型号用户和以下.用户拥有关注者和关注者,他们来自用户表本身. User.rb has_many :followings has_many :followers,:through = :followings has_many :followees,:through = :followingsFollowing.rbclass

我试图在自联接关联中的列上添加计数器缓存.
我有两个型号用户和以下.用户拥有关注者和关注者,他们来自用户表本身.

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

现在我想在追随者和追随者上添加计数器缓存.我在用户表中有followers_count和followees_count列.

我试过了

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

但是这不会返回用户表中的任何数据.
任何帮助,将不胜感激.

解决方法

很久以前,但是

User.rb

class User < ActiveRecord::Base
  has_many :followings_as_follower,class_name: 'Following',foreign_key: 'follower_id',dependent: :destroy
  has_many :followings_as_followee,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

Following.rb

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

（编辑：李大同）

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