Thanks for the reply Bill,
But my main problem is that if there is any modification corresponding to a Emp Id which is already
Present in the Old Qvd Then it will simply replace the old value whereas i want to create a flag that
some modification has been done.
I just want to capture the modification in"Leaving date " field .
If the Leaving date in new file is not equal to Leaving date
in stored qvd of the same Emp ID the Value of the flag should be= "Modified" .
store your existed file into qvd.
once you get the new file concatenate that with the old Qvd and store that with the Old qvd name and use not exists()
what bill said already.
so your new data will concatenate with old data and there wont be any duplication and you will get the modified data.