Try like this
STORE Data INTO FileName.qvd;
Hope this helps you.
The Question is not Clear here, do you want to remove duplicates while loading or you want to remove Duplicate in existing QVD?
In 1st case as Jagan told above the is the solution and in
2nd case use incremental load concept
I tried implememting incremental load but it is not giving expected result. I ahve attached the application. In that , i am getting values in SalesData1 but while concatenating it is fetching data from qvd of first occurence and not of last updated date as in case of Region é'.