Obviously, I don't know the source system and how it is structured, but in my 25+ years of database design and having worked with PeopleSoft, SAP BW, SAP HANA, Remedy, JD Edwards, and others (I am showing my age here), having the transactional data being part of the foreign key is not considered best practice.
I did not mean to doubt your thought or experience that it is not a best practice to include transaction data as part of key in source system. I thought that it might be a feasible workaround in Anaplan if anything else could not be changed.
Re: Clearing/ updating old records while uploading data into Anaplan without knowing what to clear?
I think this post has gone onto a different tangent . I will mark this as close for now .
I do want to share a sentiment though .Best practices are Best practices and we should stick to them wherever possible to get the best outcome . But guess what ? the world is not perfect . As a consultant i can advise on best practices but i cant impose best practice as a solution .