That's only possible by using the direct discovery feature of Qlikview 11.2. See here for information. In every other case you will first need to extract the data from the database. That means loading it into Qlikview in-memory database.
If you are using Qlikview 11.2, then you can use the Qlikview Direct Discovery feature, it always fetch the data from the database dynamically.
This feature is useful when your data changes frequently or you have a large data in TBs or your dashboard needs uptodate information to be displayed. When you use this the performance would be slower, because everytime it needs to get the data from database and display the charts.