How to make existing nested records read_only?

[lastobelus]

I'm having some trouble figuring out how to implement the following business logic with nests_one (or with accepts_nested_attributes_for using plain activerecord):

An Order has an Organization. When creating an order, the user can fill out organization attributes, two of which are nickname & email. However, if either nickname or matches an existing organization it should be attached to order, but not edited, which I wish to enforce in the model.

Similarly, the Organization has a Contact, with natural primary key email.

Is there a clean way to build this up with the existing ActiveType api using nests_one, or would I be better off just to use attribute organization_attrs etc. and implement the logic in the AR callbacks?

To sum it up: how do I make nested attributes act as find-or-create rather than find-and-update-or-create?

[triskweline]

AT's nested attributes were built to only cover the basic amenities provided by Rails' original nested attributes implementation. The functionality you described will need to be implemented in custom callbacks.