what is the identificator for an update?
Timestamp, recordno, flag?
As an idea:
Oldnumbers:
load recnumber from data.qvd; // load loaded recordnumbers
Tab:
load * from sourcefile where not exists (recnumber); // load only record where recordnumber not exists
load * from data.qvd; //concatenate load old datas into memory
store * from Tab into data.qvd; //store old an new data into file
drop table Tab; //clear memory
You can also do this with record timestamp
or if the record number is continuing: where recordnumber > max(recordnumber.old)
Regards
