To keep a log of customer orders in SAP Customer Data Cloud, the recommended way is to add a custom type to the Data Store and provide a UID when storing customer order documents.
* Add a custom type to the Data Store:
* Navigate to the Data Store in the SAP Customer Data Cloud Console.
* Create a new custom type that represents the order data structure.
* Provide a UID when storing customer order documents:
* When storing order data, include the UID of the customer to link the orders to the correct customer account.
* This method ensures that order data is stored separately from the account schema but can be associated with specific customers through the UID.
References
* SAP Customer Data Cloud Data Store Documentation

Within a subscription schema in SAP Customer Data Cloud, certain fields are defined to manage subscription preferences and statuses. The fields include:
* isSubscribed: This field indicates whether a user is subscribed to a particular service or not. It is a boolean value wheretruesignifies an active subscription andfalsesignifies no subscription.
* doubleOptin: This field manages the status of the double opt-in process, a security measure ensuring that the user has confirmed their subscription via a confirmation email or message. It also is a boolean value indicating if the user has completed the double opt-in process.
These fields help in maintaining the user's consent and subscription preferences in a compliant manner.
References
* SAP Customer Data Cloud Documentation on Subscription Schema