Is It Possible to Derive an Attribute from other Tables Attribute

Is it possible to derive the attribute “total cost” from “Total Cash Purchases” and “Total Salary Paid”.
Im also open for suggestion if there are any problems in my diagram. Thanks

Answer

I’m making some assumptions about what you’re asking here, based on what you show in your diagram, but if you can always calculate “Total Cost” using the values stored in “Total Cash Purchases” and “Total Salary Paid”, then there’s no need to keep “Total Cost” as a separate attribute.