SAP table T691D (Credit groups for document types)

SAP table T691D has 2 primary key fields being MANDT,CRMGR_CM.

If you're only analyzing data from a single SAP instance you may omit field MANT in your relationships as it will we the same across the entire dataset. On the other hand, if you're combining data from multiple SAP instances you need to take MANDT into account.