Ruby on Rails 多态关系的优点和缺点 [关闭]

Ruby on Rails中多态关系的优缺点及案例代码

ruby
# 创建 Comment 模型
rails generate model Comment content:text commentable_id:integer commentable_type:string
# 修改 Comment 模型迁移文件
# db/migrate/[timestamp]_create_comments.rb
class CreateComments < ActiveRecord::Migration[6.0]
  def change
    create_table :comments do |t|
      t.text :content
      t.integer :commentable_id
      t.string :commentable_type
      t.timestamps
    end
  end
end
# 修改 Article、Picture 和 Video 模型
# app/models/article.rb
class Article < ApplicationRecord
  has_many :comments, as: :commentable
end
# app/models/picture.rb
class Picture < ApplicationRecord
  has_many :comments, as: :commentable
end
# app/models/video.rb
class Video < ApplicationRecord
  has_many :comments, as: :commentable
end