I have setup an AppFlow from S3 -> Salesforce. The Id field is mapped as the unique identifier from the object in S3 to the Object in Salesforce.
When trying to UPSERT a record with a blank Id field it fails with an error:
Value of Id is invalid
I expected that a blank field would indicate that a new record should be created.
If the Id field is null, the same error is returned.
If I make up an id like "XXX" the error is:
MALFORMED_ID
How to create a new record using UPSERT?
Do I have to have an "external id" set on the Salesforce object first, and then match using that?