SAP Table
T604F Import Processing: Control Code
SAP table T604F has 3 primary key fields being MANDT,LAND1,STEUC.
If you are only analysing data from a single SAP instance you may omit field MANDT in your relationships as it will be the same across the entire dataset. On the other hand, if you are combining data from multiple SAP instances you need to take MANDT into account.