'How to Represent System in UML?
We can use Subsystem element to show breakdown of systems in UML. And, we can group Components into Subsystems.
But, is there a element to represent a system?
System here means the superset of Subsystems.
Solution 1:[1]
A system is just a component, that is composed of subsystems. And in a system of systems it will itself be a subsystem. So, each component is always at the same time a system and a subsystem - it just depends on the viewpoint of the modeler. Therefore the same diagrams can be used to show the decomposition of systems and subsystems.
In order to show, which of the components is the system of interest from your viewpoint, you can create a «system» stereotype, as suggested by @Christophe. Strangely enough, there is no standard stereotype for this, not even in SysML.
Solution 2:[2]
The only UML diagram where you see the system in the outside world is the use-case diagram. The system under consideration is represented by a surrounding box in which the use-cases are showed.
In all other diagrams, we are supposed to show some system related internals and there is no notation (nor even need) to show the whole system. In some structural diagrams, you can show larger subsystems. You show these as a component headed with the standard stereotype «Subsystem».
Now, boundaries of complex systems may be fuzzy: You may very well work on a very complex "system of systems". In this case you‘have a system made of other systems. From an UML perspective those other systems would simply be subsystems of the "system of systems".
If you need to make a clearer distinction between levels of subsystems, you could simply create an UML profile with a «System» stereotype. On the other extreme range, you could use SysML with a dedicated SoS profile.
Solution 3:[3]
Since a Subsystem is already a Stereotype of a Component in the Standard Profile, you just have to create a «System» Stereotype that also Extends the Component Metaclass in your own Profile. This is considering that the scope your system is only software and hardware with no actor activity. As Christophe mentioned, the only thing in UML representing the system is the subject which surrounds its Use Cases, the subject not even being a Model Element...
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Axel Scheithauer |
| Solution 2 | Christophe |
| Solution 3 | Jean FEX |