DART

how create migration rails

rails g migration AddPartNumberToProducts

ruby on rails db migrate

rails db:migrate

using SQL in rails migration

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

ruby on rails db migrate

namespace :schema do
  desc 'Creates a db/schema.rb file that is portable against any DB supported by Active Record'
  task :dump => [:environment, :load_config] do
    require 'active_record/schema_dumper'
    filename = ENV['SCHEMA'] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, 'schema.rb')
    File.open(filename, "w:utf-8") do |file|
      ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, file)
    end
    db_namespace['schema:dump'].reenable
  end

  desc 'Loads a schema.rb file into the database'
  task :load => [:environment, :load_config, :check_protected_environments] do
    ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:ruby, ENV['SCHEMA'])
  end

db:migrate rails with version

$ bin/rails db:migrate VERSION=20080906120000

rails migrate code

hola mundo