rails transactions

manual_rollback.rb

ActiveRecord::Base.transaction do
  raise AcitveRecord::Rollback if something_bad_happens
end

place_order_with_transaction.rb

def place_order
  ActiveRecord::Base.transaction do
    item = Item.some_scope
    item.reserve!
    order = current_user.new_order(item: item)
    order.save!
    invoice = order.new_invoice
    invoice.save!
  end
end

place_order_without_transaction.rb

def place_order
  item = Item.some_scope
  item.reserve!
  order = current_user.new_order(item: item)
  order.save!
  invoice = order.new_invoice
  invoice.save!
end

transaction_block_with_return.rb

object =  ActiveRecord::Base.transaction do
            item1 = Item.create_1
            item2 = Item.create_2
            [item1, item2]
          end