I’m currently updating my materials for the upcoming Masters Summit for QlikView in Chicago, and thought I’d share a little bit with you. In my session on data modeling, I explain how you can deal with various types of Slowly Changing Dimensions in QlikView. One of the techniques I explain is using hash functions to detect changes in (historical) records. During the previous events, this always lead to two questions from the audience:
- What exactly are hash functions and hashes?
- And, from those who already know the answer to the first question: Aren’t you worried about hash collisions?
Today I will answer both questions and hopefully give you some insight into hash functions, their usefulness in QlikView and the risks of hash collisions.
