Introduction Dan Linstedt, the inventor of Data Vault, has written a lot about it: hashkeys. For instance, one of his latest blog posts: #datavault 2.0, Hashes, one more time. I will not list all other sources, as you can use Google yourself. A few comments on hash keys: You need them for scalability. Using sequence numbers is taking the risk that your data warehouse does not scale well later when...
Read MoreIntroduction I must admit I have a weakness for British humour. When I had to cope with leading zeros in business keys some time ago, I spontaneously came up with the title of this post, not knowing that it would serve as such. For those who do not know, "Meetings, bloody meetings" is a British comedy training film in which John Cleese plays a main role. It was...
Read MoreIntroduction This weeks post is about the LoadDate and LoadEndDate. Actually there are two things to be nerdy on: End dating without gaps Getting the best value for bytes on DATETIME2 precision By the way, these topics apply to SQL Server, the examples are made using SQL Server 2014. 1. End dating without gaps How end dating works In a Data Vault Satellite, different subsequent versions of a row in the source...
Read MoreWe need ambassadors! I was at this one day course recently and spoke to a professional working in the business intelligence domain. He said that he had just followed a two week course for datawarehouse architects. I asked him, what did they tell about Data Vault? His answer was shocking: "Not so much .." If recently trained datawarehouse architects do not get trained to use Data Vault in a datawarehouse...
Read MoreUpdates Change log DateChanges 31 January, 2017Really good news! The 8k limitation on HASHBYTES has been removed in SQL Server 2016! Today I would like to discuss Hash Diff calculation using SQL Server 2014, from my own experience. My purpose is NOT to be complete and/or to replicate book "Building a scalable data warehouse with Data Vault 2.0". For full details please read the book. However I will give a short...
Read MoreIntended audience This post could be interesting for professionals working on datawarehouse projects using the Microsoft SQL Server database engine. This post assumes that you have at least a basic understanding of Data Vault principles. Introduction Those who have read the book "Building a Scalable Data Warehouse with Data Vault 2.0" by Dan Linstedt and Michael Olschimke will know that database schema's are used in the examples in...
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