Using an ETL approach to create QVD data layers
We now know that there are very good reasons for adopting an ETL approach to loading data in QlikView. Now we need to learn how we should go about implementing the approach.
Each part—Extract, Transform, and Load—has its own set of recommendations because each part has a very different function.
Essentially, the approach looks like this:
The approach can be explained as follows:
- Extract the data from data sources into QVDs.
- Transform the data from the initial QVDs into transformed fact tables and conformed dimensions.
- Load the transformed QVDs into the final applications.
The final two layers, the transformed QVDs and the final applications, become potential sources for a user's self-service. We can have confidence that users who load data from these layers will be getting access to clean, governed data.
Creating a StoreAndDrop subroutine
When we are loading data to create QVDs, we will end up calling the Store statement quite frequently...
