We have a database that we can connect to via ODBC through MS Access. This is all raw data. Our business has its own terminology on how to classify each account in the database. I tried to use functions to help classify each account using our business rules but because of the size of the database, the queries would take a long time to run. So I then tried using IIF statements instead of functions and it made some of my queries extremely complex and unable to run.

I think I'm doing this classification process all wrong. Can anyone point me in the right direction?