Hash keys can be used instead of sequence numbers to build surrogate keys in a Data Warehouse. This is often done in Data Vault environments, and there are some good reasons to do that. But there are also several issues and restrictions with hash keys. So, use hash keys only if you have good reasons for them. And if you decide to use hash keys in your Oracle Data Warehouse, make sure that you do it the right way.
A good idea when working with Data Vault is to generate the tables and load processes to avoid a lot of manual development. biGENiUS, the Data Warehouse automation tool of Trivadis, is now able to generate Data Vault objects.
Data Vault is getting more and more popular for modeling Data Warehouses. Some of my colleagues asked me for book recommendations about this modeling method. Here a short review (from my personal point of view) of two Data Vault standard books.
Three intensive and exciting days at the DOAG conference in Nuremberg are over. Once again an impressive event with many presentations, good discussions and a lot of socializing. Here a short summary of my impressions and my presentations.
Loading data into a Data Vault Model is easy. But how complex is it to extract the data from a Data Vault into a dimensional Data Mart? A Point in Time (PIT) table helps to load Dimensions from a Hub with multiple Satellites.
Ensemble modeling is a family of data modeling approaches optimized for data warehouse. Its basic idea is to break things into parts to increase flexibility and to change them independently. A group of people met in Stockholm to find the least common denominator of several ensemble modeling approaches. I had the luck to be invited to this “ensemble dinner”.
The Oracle OpenWorld 2014 just finished yesterday, but unfortunately I was not able to attend this great conference this year. Perhaps next year – who knows…
But I had the luck to give several presentations in the last few years on Oracle OpenWorld in San Francisco, on the DOAG Conference in Nuremberg and on some other German conferences. Now you can find all these presentations on SlideShare. Because most of the slides are not brand new, my Trivadis colleague Silvana Bernasconi reformatted the older presentations to the current Trivadis PowerPoint template (thank you, Silvana). Nevertheless I promise: The contents of all these presentations is still up to date. Enjoy to have a look at and probably download some of the presentations.
An overview of all my presentations you can find on the Presentation page.