I see one problem here.You said that you have scenario where you don’t want fields to be updated.
Are those standard fields.If yes there must me reason for update.Would be good if you can provide entity name and fields you are trying not to get updated.To avoid data consistency issue.
This will also help us to provide where to use methods in Entity level or is it something you also want to implement in General CRUD operation.
This can give us direction if this to be done in table level itself then…
Thanks and have a nice Day!