System and Subsystem

[kwasposer]

I try to explain my new issue:

I have two Models. Each of them describes a system context in a bdd diagram.

The second system (Model 2) is using the first system (Model 1) as a subsystem. So i dragged the system block of the first system in the system context of the second system.

Is it correct that the first system in the second system is still named <<system>> and not <<subsystem>>.

But changing the stereotype to <<subsystem>> will change the stereotype in the Model 1, too. But in the Model 1 it is still the <<system>> itself.


Sorry that i am so picky. Hope you get my point and get me on the road again.

[Richard Freggi]

Hi, if you specified model 1 as a system, that's what it is.  You can't change its type on one diagram and expect it to have a different type in another diagram.  It can't be 2 different things.
Think about it this way, all diagrams are nothing else that different views of one and the same model.  Think about the model not about the diagram. What is system 1 in the model?  If it is a system, then that's what it should be in all views.

[kwasposer]

Thanks Freggi. I was beleiving, that all <<system>>s which are part of another <<system>> should be defined as <<subsystem>. Sometimes I am maybe to correct.

[qwerty]

You can make element look different on different diagrams. For that you need to create your own profile (to be deployed with your own MDG) where stereotyped elements use shape scripts and alter the element appearance depending on which diagram type the element appears. Personally I haven't done that, but there are threads here where the approach has been discussed. Quite a bit of work anyway.

q.

[Richard Freggi]

I was beleiving, that all <<system>>s which are part of another <<system>> should be defined as <<subsystem>. Sometimes I am maybe to correct.

Well, that's not how UML works...
UML puts some constraints into what you can/cannot do, and my experience that they are hugely beneficial for model definition, expansion, maintenance, reuse, communication to others... one such constraint is that if an apple is an apple, then it's an apple... it cannot be an apple here and a banana there.
But you can use inheritance and realize dependencies and other ways to do what you need without breaking the model.

[kwasposer]

Hello Richard Freggi,

can you give me an example?

System A : Heating System <<system>>
System B : House <<system>>

But how can I reuse System A as a compartment in System B. In the System View of System B, System A is a <<subsystem>>. But in  the system view of System A , System A is a <<system>>.

If I have linked System A as a compartment to System B, I would like to have still the possibility to jump to the Model System A.

[Richard Freggi]

Hello Richard Freggi,

can you give me an example?

System A : Heating System <<system>>
System B : House <<system>>

But how can I reuse System A as a compartment in System B. In the System View of System B, System A is a <<subsystem>>. But in  the system view of System A , System A is a <<system>>.

If I have linked System A as a compartment to System B, I would like to have still the possibility to jump to the Model System A.

I can recommend any good UML book