I'm trying to import CreatedDate and CreatedById from SQL server to Salesforce for an object. According to Salesforce, we can only Insert, not Update/Upsert these two fields. In Salesforce, I already have some existing records. So, I have to separate the task into two: update the existing records, and upsert the new records. I'd like to know if there's a workaround for this so that I can just upsert the fields without having to manually determine which one already exists?