I have been reading about Non-historized Links which are mostly used to meet use-cases where we get immutable data events such as data from IOT, sensor etc.
I see a mention of Non-historized satellite in the book “Building a scalable data warehouse with Data Vault 2.0”. In the scenario mentioned in the book on Page 135, Non-historized satellite is seen hanging off a Non-historized Link.
From Data Vault standards, Can a Non-historized satellite be attached to a hub directly?
Why do you want that? The descriptive data is stored in the NHL, no need to hang a satellite on a NHL.
Yes… as long as the NH-Sat is about that single business entity.
NH-Sat rarely gets mentioned but it is a pattern
Agreed, a Non-historized Satellite on a Hub is not a violation of the “standards”. However, as Patrick points out, there are a few considerations:
Is it about a single business concept (Hub). Very often “transactional” data by its very nature is conveying data about multiple business concepts (Hubs), which is why it often manifests itself as a Non-historized Link.
Second, is the data at the same grain as the Hub? Again, transactional data is often at a lower level of granularity than the associated business concept. For example, I work a lot in healthcare. A healthcare “Claim” has a business key for the claim and therefore is a good candidate for a Hub. Each claim has multiple “Claim Line Items”, which may be another Hub linked to Claim, or a Multi-active Satellite off the Cliam Hub by “Line Number Sequence”
Now comes the tricky part. Claim lines get multiple adjustments as a claim gets adjudicated. Some may get denied initially, then reinstated, then the billed amount on that line may change, etc. Lots of transactions against one line…different grain.
Once you work through these kind of modeling questions, if there is appropriately some kind of transactional type data applicable to a single Hub, then that’s where it goes.
Let the data tell you