migration rails code example

Example 1: Add references rails migration

class AddUserToUploads < ActiveRecord::Migration
  def change
    add_reference :uploads, :user, index: true
  end
end

Example 2: how create migration rails

rails g migration AddPartNumberToProducts

Example 3: ruby on rails db migrate

rails db:migrate

Example 4: rials db down

bin/rails db:migrate:down VERSION=YYYYMMDDHHMMSS

Example 5: using SQL in rails migration

def change
  execute <<-SQL
    UPDATE table1
    SET column1 = "value"
  SQL
end