Forewarning: this does not pertain to mapping data to the CDM. Rather I am mapping source data about medical devices to a new target format.
I know generally which source fields match with which target fields, but I think I need a set of rules to convert source values to target values. I envision either writing rules as columns in a spreadsheet (input/output) or as if/then statements in plain text. Once I have those rules, I will have SQL queries process the actual conversion.
Would either of those be the best practice for this stage of ETL? The OHDSI manual mentions that the ETL is split into a planning/design phase and then a technical execution phase. Where does explicitly matching source values to target values fit into the ETL process?