Author Topic: BPMN: Data objects vs Classes?  (Read 2654 times)

Svend Erik Nygaard

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BPMN: Data objects vs Classes?
« on: October 10, 2014, 02:24:06 am »
In my concept/information model I have classes representing physical objects as well as information objects. We have definitions, descriptions and a ton of other valuable specs/connections associated with these clases.

However in BPMN it is suggested that I use a ”Dataobject” element (as physical objects or information objects).
On the DataObject I can specify an ”ItemDefinition” element, and then on the Itemdefinition I can specify my class from my conceptual/information model. To me this is a lot of indirection a lot of extra work and elements:
DataObject.itemSubjectRef -> ItemDefinition.structureRef -> Class
That gives me three elements instead of one.

EA BPMN actually does not prevent me from using my Class elements directly with the BPMN data associations instead of the DataObject elements. So I’m very tempted to just use my classes directly in BPMN (or instances – or instances with states)
Is that a bad idea? Have I misunderstood the way to link from BPMN to my classes in concept/information model?
« Last Edit: October 10, 2014, 03:33:41 am by svenderiknygaard »

qwerty

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Re: BPMN: Data objects vs Classes?
« Reply #1 on: October 10, 2014, 05:45:10 am »
I'm not a BPMN guru but I guess that when you deal with business processes you refer to objects, not classes. So at least you should take instances.

q.

ken.norcross

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Re: BPMN: Data objects vs Classes?
« Reply #2 on: October 10, 2014, 07:16:39 am »
If you are not going to fully define your BPMN and then execute it with a BPM engine, then it doesn't seem to help much to use all of the layers of indirection.

As a middle ground, you could use the BPMN elements in the BPMN diagrams and then "trace" them to UML elements of your data model, probably in another mapping diagram. This would just allow you to keep the two modeling languages separate, and you would have 2 elements + 1 relation, reducing complexity a little.

Ian Mitchell

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Re: BPMN: Data objects vs Classes?
« Reply #3 on: October 13, 2014, 11:42:34 pm »
I teach BPMN quite a bit  (that doesn't mean I'm a 'guru')  but I favour simplicity of your meta-model over BPMN purity any day.
The downside is, of course, that a readers of your BPMN diagrams will see Classes where they expect Data Objects, but most people with even a little UML/BPMN knowledge should get the idea.
So my advice would be 'keep it simple' and use Classes. And make a note of your decision in your meta-model documentation - you DO have a documented metamodel don't you... ;)
Ian Mitchell, Designer, eaDocX


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Jacob Vos

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Svend Erik Nygaard

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Re: BPMN: Data objects vs Classes?
« Reply #5 on: October 22, 2014, 12:05:38 am »
(I'm back on the BPMN stuff now)
Thanks everyone. At least I can see, you have the same considerations as I do :-/
I think I'll have to use instances (either DataObjects or Class Instances) - if not for other reasons then in order to present multiple instance states of the same class in multiple places on the same process diagram.
« Last Edit: October 22, 2014, 12:08:58 am by svenderiknygaard »