At the moment we have a QVD-file with all the data from our database.
The plan is to do an incremental load every day or week, so we get a second QVD with only the new and modified data from our database.
Then every time we do an incremental load, we want to merge this data into our original QVD, so that we only have 1 QVD with all the data.
For the new records, this would be no problem, because they are just being added to the original QVD. But for the modified records, this would give us some problems, because we can't just add them to the original QVD, because we would have double data.
So we should have a method to check if there already exists a record inside the original QVD with the same keyvalue, if not, just add the record to the QVD, if yes, overwrite the existing record in the original QVD with the record from the QVD from the incremental load.
