Figure 5 shows the SM corresponding to the CM of Figure 4. The diagram (an Object Fact Diagram),
plus the table below it (an Object Property Table) may be viewed as a variant of the ORM model discussed
in section 3. 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 facts (relationships) that can be observed, as well as the laws that appear to hold for the co-existence of these things and facts. The gray-colored boxes depict external object classes. They contain
objects that play a role in the business processes, but their existence is determined by transactions other
than those in the CM. The white-colored boxes depict internal object classes. The objects in these classes
are created in the mentioned transactions. For the classes Membership, Loan, and Shipment, this is obvious.
For BookCopy, these are the books delivered in shipments to the library.
The diamond shaped fact types are the production fact types that also appear in the Transaction Result
Table of Figure 4. These fact types link the conceptual schema of the production world to the transactions
that change the state of the production world. Consider the creation and termination of loans. There are two
'normal' fact types: "the membership of L is M" and "the book copy of L is C". A uniqueness constraint
holds for the role of the loan in both fact types: a loan always relates to at most one membership and one
book copy. A mandatory constraint also holds for Loan in both fact types. Hence a loan always relates to
exactly one membership and one book copy. Therefore, the fact types "the membership of L is M" and "the
book copy of L is C" are existentially dependent on Loan.