In the following example the FN$FORMAT_DBKEY function returns the
       dbkey of the last record read from CITY_CODE_TABLE in its string
       format.

       DTR> PRINT FN$FORMAT_DBKEY(FN$LASTREC_DBKEY("CITY_CODE_TABLE"))
                  FN$FORMAT
                        DBKEY

       11:149:26
       DTR>