It’s been a while (busy, busy) but I though this one would be a good candidate for another ArchiMate quiz. This time not “What is wrong with this picture’, but more, “This is grammatically correct, but why? And what does it mean?”Have a look at the following two snippets (in Mastering ArchiMate colours, where ‘deep’ is technology and ‘light’ is business, and blue is active, yellow is behaviour and green is passive, as it was originally used in ArchiMate).
There are two Assignments here. Between a Device and another Device. And between a Communication Network and a Business Actor. These are valid relations in ArchiMate 3.
The question is: why is this the case? They are not direct (core) relations, they are derived. But how? And what do they mean?
Any good answer (either technically or because of entertainment value) added below in the comments may win a free PDF bundle of Mastering ArchiMate and Chess and the Art of Enterprise Architecture. If you have images to add, mail them and I can add them to your answer.
My starter for ten…
Device A is assigned to a technical function that serves the function that Device B is assigned to (or realizes). A good example would be that Device A is a peripheral assigned to Device B.
Similarly the communications network realises a technical function that serves the business function that Organisation (Actor) A is assigned to. My example would be a private network supporting a subset of users of a company that are working on sensitive material.
Why would someone wish to model them… maybe over time the peripheral might get reassigned or the modeller wishes to understand the relationship between the Device/Network and some other structural entity in order to understand capacity limitations.
The question is: how is this supported by core relations and derivations of those. With realisations and serving in place, you can’t get assignment as a result. Both assignments are derivations in ArchiMate. Of what?
Oops got the table the wrong way around – but the first example can be easily fixed by an aggregation (or composition…
Device B is assigned to a function that aggregates the function that Device A is assigned to
For the second one, I am not 100% but appears to work using a location namely the network is assigned to a technology service that is aggregated at a location that is assigned to the business actor
Nope both are not allowed derivations because not all relations run in the same direction. See Section 9 Derived Relations in the free syntax excerpt of Mastering ArchiMate.
If derivation is based on strength of the relations. Since assignment is the strongest (I should check before I’m sure.)
So the full picture of the object chain should be made up of assignments?
Then I could imagine it could be a lot of cases… Tech or medical.
Derived structural relations are based on taking the weakest in the chain. Just try to create a chain from in core metamodel that ends up being an Assignment (in either case). Answer that, and you’ve answered the quiz question.
For the first, I’m thinking of some kind of virtual machine (device A) that’s being assigned (at run time) to a Node consisting (composed) of physical device B.
Sure that sounds OK as a use for that relation, but (1) according to ArchiMate “A device is a physical IT resource upon which system software and artifacts may be stored or deployed for execution” (my emphasis) and (2): the quiz question is: how is this relation derived? What route is there in the metamodel that allows this derivation (as it is not a core relation)? The quiz question in part is: create a derivation that results in Device Assigned-To Device.
I had too things in mind to solve this quiz:
1. In order to get the assignment derived relationship I can go from one element to other just using assignment relationship or stronger one (composition or aggregation)
2. If there is an specialization relationship, I can use composition or aggregation relationships between same type elements considering specialized elements as being the same type too
For the first case:
– A device is assigned to System Software
– System Software and device are both specialization of node. I can use the composition relationship between them, so I can say that a system software is composed of a second device.
– The weakest relationship is assigned-to, I can derive a assigned-to relationship from system software to device
For the second case:
– A communication network aggregates a device
– Device and facility are both specialization of node. I can use the composition relationship between them, so I can say that a device is composed of a facility.
– Facility has a assigned-to relationship with business actor
– The weakest relationship is assigned-to, I can derive a assigned-to relationship from communication network to business actor
Still thinking examples for these cases…
Now, the additional question was: what do these cases have in common? I’ll wrap it up later.
At least one common factor is the specialization of Node which you can exploit to create interesting derived relationships. (Like Raquel’s “device is composed of a facility.”)