You can go with the following method:
1. Consolidate the internal table.
2. After consolidating the internal table, use MODIFY command.
e.g.
******************************************
Loop at itab1 into wa1.
*populate itab .
Endloop.
MODIFY dbtab FROM TABLE itab.
COMMIT WORK.
******************************************
(dbtab: Database table to be updated.
itab1: intermediate internal table.
itab: Internal table, consolidated with desired data.)
