Do attachments have the same storage and transaction cost rules as resources themselves?

Question

We are implementing a field that may sometimes get big in specific admin-controlled occasions and are evaluating using the new Cadence attachments feature to define that field vs having the field on the resource itself. Do attachements have the same storage and transaction cost rules as resources?

Have not used attachments yet.

Answer 1

Adding an attachment has to be done in a transaction so it has the same rules.

Answer 2

Yes, attachments can be thought of as a nested structs/resources, so have the same storage and transaction costs as a field that was explicitly defined in the base type.