Hash keys are often used as primary keys in Data Vault environments. When loading dimensional data marts from a Data Vault schema, it seems to be obvious to use them as dimension keys, too. At least in combination with Oracle Database In-Memory, this is not a good idea.
In the last couple of days, I joined several interesting events in Colorado. First, I was able to take part of the “Advanced Data Vault & Ensemble Modeling Summit” at Genesee Academy. After that, I attended the first “Global Data Summit” conference in Golden, Colorado. And finally, I was invited to a very special dinner of the “Boulder Business Intelligence Brain Trust”.
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.