How to do rollbacks in Ruby on Rails in case of bad situations?

Question

Ruby on Rails

Let's say there are models:
Subscriber (subscriber)
Subscription (subscription)
Period (subscription periods).
All of them are interconnected, that is, a subscriber can have several subscriptions, and subscriptions can have several periods.
And when adding a subscriber, there must be a subscription, and the subscription has a period.
So when adding in the controller, it is usually added like this.
First subs = Subscriber.create()
Then subscription = Subscription.create(subscriber_id: subs.id)
period = Period .create(subscription_id : subscription.id).
Question: what if the Subscriber is added, but the rest are not (for example, the Internet disappeared immediately after adding the Subscriber), because all of them must be mandatory?
Yes, you can write "use transactions", but this concept is loose. Could you give an example?

Answer 1

Frankly speaking, I do not see the need for manual use of the transaction here. If the client has already sent the form and the server has received the data, then the form data will be processed by the rail, regardless of who lost the Internet. I would recommend doing something like this (I think this code is more ideologically correct):

subscriber = Subscriber.new
subscription = sub.subscriptions.build
subscription.periods.build
subscriber.save

This code will indeed require properly configured links.