ow to change the key value for session runs ?

[vikind]

have two tables MEM and PROV there is a RUN_kEY that has to be populated
in both the tables and there is one another "SESSION_RUN" table that contains the RUN_KEY
The Run_key should have values like for the mapping that loads the MEMBER table the run_key should be
1 for all the records and for mapping that loads the Provider table the value of RUN_KEY should be
2 for all the records. and say if i run my Mapping for Member table again it should have a new
RUN_KEY value of 3..ie..if i am running say 5th session the run_key should have 5. and at the same
time my SESSION_RUN table should contain information like

SESSION_RUN
-----------
RUN_KEY | Mapping Name

1 LoAD_MEM
2 LOAD_PROV
3 LOAD_MEM

..

so on

i tried to use a sequence to generate the RUN_KEY but the problem is
sequence generator will increment for each row.. the other thing that
i thought of was to use a mapping variable but again
the mapping varaible (setCountVaraible) will increment for each row and
it will not be constant for all the rows for each mapping for populating the
RUN_KEY



thanks in advance for ur help!