Database Reference
In-Depth Information
roles; they are colored gray. Actually, what is inside the boundary is the 'uncovering' of the
system actor role S01 (Library).
The table below the diagram (called a Transaction Result Table) lists all transaction
types and specifi es for each the resulting P-event type. Actor roles A09 and A10 are self-
activating actors: they are both initiator and executor of the same transaction. This is how
DEMO models periodic activities.
Figure 4 shows the SM corresponding to the CM of Figure 4. The diagram (an Ob-
ject Fact Diagram), plus the table below it (an Object Property Table) may be viewed as
a variant of the ORM model discussed in this chapter. They specify all object types and
fact types occurring in the action rules of the AM (of the B-system). The SM of (a part of)
an organization is an
ontological
conceptual schema—it describes the types of things and
ontological
facts (relationships) that can be observed, as well as the laws that appear to hold for the co-
Figure 4: DEMO State Model (SM) of the library
