Nesting and implicit

Uit Via Nova Architectura Wiki
Ga naar: navigatie, zoeken
Figure 2 02 Most Important relationships between concepts.png ArchiMate Made Practical

Zie ook: ArchiMate in de praktijk

Question

When nesting concepts, do the relationships of the nested object also implicitly apply for the 'parent' object?

Solution

The concept of ‘nesting’ is not formally defined in the ArchiMate language. In practice however various forms of nesting occurs

1. A visual representation of nesting different concepts

Figure 5 31 Nested concepts.png

Figure 5 50: Mix of nested concepts

The advantage of this form is the relatively simple view where relationships are abstracted between different objects towards ‘there is a relationship’. The disadvantage is that in this view it is not known what the exact relationships between the objects are.

2. Hierarchical decomposition

This form of nesting is often used to decompose the same concept into sub concepts. Examples are hierarchical process, function, or organizational structure. The following example shows a process hierarchy.

Figure 5 32 Nested through process hierarchy.png

Figure 5 51: Nesting through a process hierarchy

Variant 1 indicates the visually nested sub-processes. The relationships between the sub processes and the main process are not visible (but should formally be modeled).

Variant 2 indicates, in this case, the composite relationships between objects. When nesting between the same concepts it is common to use the composition or aggregation relationship.

Both variants model Subprocess-3 with an Access relation towards Object-1. Subprocess-3 is decomposed from Main Process.

According to the rules of derived relations (see good practice 'simplifications and preservation consistency') it holds true that the main process also has the Access relation has with Object-1. Hence with this type of nesting the ‘parent’ object has the same relation as the child object.

Note: Composition or decomposition of a concept is not the same as clustering of similar concepts. For the latter, the concept of 'Grouping' may be used

Figure 5 33 Clustering using grouping.png

Figure 5 52: Clustering using grouping

Consequences

When ‘visual’ nesting of objects the relationships between these objects must be explicitly described.

Alternatives

Not applicable.

Relationships with other good practices

See also good practice: 'Simplification and preserving consistency'