Again, thanks for the kind replies.
The idea of run read only process against SQL db is possible, like what you’ve said, if we need the historical data only for reporting purpose, but I am still discussing this matter with AS/400 system analyst.
My next question is, if we need to modified this historical data is AS/400 (this modification process is not possible in SQL, for example). So, my approach for deleting the data in SQL, transfer to AS/400, modified in AS/400, and transfer back to SQL is right? Or there’s another better or effective way?
(another problem just pop up from my head just now, what happen if different user is requesting same historical data at same time, since he wont find the data, I’ve already deleted it in SQL for the first user that request the data.. I will try disccuss this more with the SA.)