Modeling of link: reference a hub by businessKey instead of hashKey

Data Vault 2.0
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I have a hub (hub_entity1) with 2 businessKeys and a hashKey which is composed of them.
I want to reference this hub by a link table , but I want to reference only the businessKey (so a whole set of rows) instead of the hashKey (referencing a single row). Is this allowed in DataVault Modelling to directly reference a businessKey from a hub or do I need to introduce a new hub for it?

Datavault-Modelling
Datavault-Modelling750Ă—339 11.9 KB

2

Hi Jules

Is this allowed in DataVault Modelling to directly reference a businessKey from a hub

This is an interesting use case. I think you’ll find the answer is likely “No” I don’t think this is allowed and would be considered against standards. Hash keys are optional (but recommended) so business keys aren’t banned from being in links obviously but referencing only one half of the entity combined key is making me think this would add intricacies to maintainance down the line.

My main thought is why is this the approach you’re taking? My only thought is that it reduces the number of columns in the link but this isn’t really that big an issue given how narrow that table is. Is it a “one to very many” relationship or something like that?

Splitting the hub just to handle these keys separately also sounds like an odd choice to me but could be the way to go if there’s a genuine distinction between the two BK entities. I’d assume they’ve been grouped into one hub for a reason though and would suggest just going hash key to hash key.

Please feed back with more info and there might be a better answer for your specific use case!

Frankie

1 Like
3

Hi Both,

I agree with Frankie: don’t go there.
Consider the reason why you would want to do so? Is the one half of this BK identifying a Business Object on its own? In that case, introduce an additional hub for that one (plus a link with your current hub).

Klaas

4

Hi everyone ;-),

Without feedback from @julesKr, we can only speculate. To me, it sounds like this combined business key has a different granularity than the individual business key referenced by the link.

“Different granularity, different hubs” (and a link between them).

If the two components of the Business Key represent two different identifiers for the same business object, each individual component identifies the business object.

In other words, each key gets an entry in the hub, and a Same-As Link connects the two.