To prevent duplicate Order records from being created when updates come from the OMS:
Option B: Use the order number from the OMS as an external ID.
Option D: Ensure that the order number in the OMS is unique.
Why These Actions Prevent Duplicates:
By using upsert with the External ID, the integration can update existing orders instead of creating new ones.
// Example of upsert operation using External ID
upsert orderRecord Order_Number__c;
*
Reference:
"An external ID is a custom field that has the 'External ID' attribute, meaning that it contains unique record identifiers from a system outside of Salesforce."
- Salesforce Help: External ID Fields
* Why Other Options Are Incorrect:
Option A: Using the email on the Contact record as an External ID does not prevent duplicate Orders.
Option C: Writing a trigger to delete duplicates is not proactive and adds complexity.