It depends. Do you need to reuse the data in other apps? Then store the data in a qvd and reuse it for all the apps that need that data. Do you need to do incremental (aka delta) loading and keep track of historic data? Then store the data in a qvd and each day (or week/month/whatever) load only the new data from the source and append it to the historic data from the qvd. If you have no reason at all to store data in an intermediate qvd file then don't.