Code Explainers

Code explainers tagged #migrations

ruby 
class Comment < ApplicationRecord
  belongs_to :commentable, polymorphic: true, counter_cache: true
  belongs_to :author, class_name: "User"
 

How polymorphic comments work in Rails

polymorphic-association concerns counter-cache
Intermediate 8 steps
ruby 
class CreateCommentsWithCounterCache < ActiveRecord::Migration[7.1]
  def change
    create_table :posts do |t|
      t.string :title, null: false

How counter caches work in Rails

counter-cache migrations associations
Intermediate 6 steps