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

Looking at ActiveRecord::Persistence, everything ends up calling create_or_update behind the scenes.

def create_or_update
  raise ReadOnlyRecord if readonly?
  result = new_record? ? create : update
  result != false
end

So! Just:

def readonly?
  !new_record?
end