Thanks again, Eirikur. I've been thinking along similar lines as far as how the table structures would look. The fun part (as Phil suggested) is figuring out how to enforce the hierarchy in this setup. A row in the target table might contain data that meets multiple mapping rules, and I want to be sure that I always get the appropriate match based on the hierarchy established in the business rules. I think I'd either have to perform multiple updates (one update statement for each source column value, not the optimal solution in my opinion), or use dynamic SQL to build a case statement-based update that looks like what I started out with, but using this table as a driver. I'd probably add a sequence number to the table to use as an ordering mechanism when building the dynamic sql. Does that make sense or is there a simpler solution that I'm not seeing here?