Is there an easy way to make a Rails ActiveRecord model read-only?

Question

I want to be able to create a record in the DB but then prevent Rails from making changes from that point on. I understand changes will still be possible at the DB level.

Answer 1

A custom validator can do this:

validate :nothing_changed, unless: :new_record? # make immutable

...

def nothing_changed
  errors.add(:base, "Record is read-only") if self.changed?
end