Tagged: Driving Key


NoETL – Data Vault Link Satellite tables (part 2)

This is the second part of the Link Satellite virtualisation overview (the first post on this topic is here), and it dives deeper into the logic behind Driving Key based Link Satellites. Driving Key implementation is arguably one of the more complex things to implement in Data Vault – and you (still) need to ensure you can cover reloads (deterministic outputs!), zero records / time variance and things such as re-opening closed relationships. In the example...


NoETL – Data Vault Link Satellite tables (part 1)

The final of the series of planned posts (for now at least) about Data Warehouse Virtualisation is all about Link Satellites. As with some of the earlier posts there are various similarities to the earlier approaches – most notably the Satellite virtualisation and processing. Concepts such as zero records and ‘virtual’ or computed end-dating are all there again, as are the constructions of using subqueries to do attribute mapping and outer queries to calculate hash...


Driving Keys and relationship history, one or more tables?

Handling Driving Key type mechanisms is one of the more challenging elements of Data Vault modelling. It’s not necessarily difficult to implement this concept, but more how to interpret this and get the right information out of the Data Vault again. In this post I’ll explore two ways of storing relationship history over time: Using a separate table to store Driving Key information and a separate table to store normal relationship history (type 2) and,...