Databases Reference
In-Depth Information
Figure 2). This I-system supports the B-system, which represents the abstracted essence
of the organization. The kinds of support are purely informational: collecting, providing,
recalling and computing knowledge about business acts and their results. The AIS and the
BS can each be modeled as a discrete dynamic system (or discrete event system) (Hee, van
Houben & Dietz, 1989), but of a different category—a BS is a social system, whereas an
AIS is a rational system.
An AIS is a software system, so the only support it can offer is to provide information
to the BS that is modeled in the AIS. Only in the BS may original facts be created (which
can then be entered in the AIS). For example, the replenishment orders generated by an
automated stock control system are just (computed) output information as far as the AIS is
concerned. At the I-system level they are not business orders. Only by virtue of the declara-
tion by the B-system do these information items count as replenishment orders.
The second contribution offered by DEMO to the design of an IS is a full account of
the possible actions to be supported. The operating principle of a BS is the ability of human
beings (in their role of social individuals) to enter into and comply with commitments and
agreements. This was called coordination in this chapter. The standard pattern of C-acts and
resulting C-facts of a transaction is shown in Figure 10. An open or white box represents a
C-act type and an open or white disk represents a C-fact type. A gray box represents a P-act
type and a gray diamond a P-fact type.
The initial C-act is drawn with a bold line, as is every terminal C-fact. The gray
colored frames denoted by “initiator” and “executor” represent the responsibilities of the
two partaking actor roles. The steps in the transaction process are ideal candidates for the
functions (use cases) of the AIS. These are the atomic components of business processes;
Figure 10: The standard pattern of a transaction
