what is transaction key or process key in sap co

Transaction key  /process key

a) BSX                  Inventory postings

b) WRX                Goods receipt /Invoice receipt (GR/IR)

c) PRD                  Price difference /Production order differences

d) GBB                 Offsetting entry for inventory postings

                          (i) VBR consumption

                          (ii) VNG Scrapping

                          (iii) BSA Opening stocks

                          (iv) ZOF Production receipt without production order

                          (v) AUF Production receipt with production order

    (vi) VAY Delivery where sales account is created as revenue            element (CO implemented)

    (vii) VAX Delivery where sales account is not created as                  revenue element (Co not implemented)

    (viii) AUA production order differences

Eg: 400000 Raw material consumption

       200121 Inventory raw material

For consumption

Raw material consumption     Dr

            To Inventory raw material

For GBB                     VBR                Assign account no.400000

For BSX                                              Assign account no.200121