Modeling Business Rules with Situation/Activation Diagrams

Business rules are statements about business policies and can be formulated according to the event-condition-action structure of rules in active database systems. However, modeling business rules at the conceptual level from an external user's perspective requires a different set of concepts than currently provided by active database systems. This paper identifies requirements on the event language and on the semantics of rule execution for modeling business rules and presents a graphical object-oriented language, called Situation/Activation diagrams, meeting these requirements.

Situation diagrams provide a high-level graphical representation of logical events for the conceptual modeling of business rules. A logical event is specified declaratively as a graphical query with temporal and logical conditions over members of object classes, event classes, and interval classes.

Activation diagrams specify graphically which transactions either have to be performed immediately upon a temporal event or have to be asynchronously initiated upon an arbitrary event. Activation diagrams are based on an execution model that guarantees a ``temporally faithful'' execution of business rules and user transactions. Informally, temporal faithfulness means that transactions requesting to commit after a temporal event triggering some business rule are serialized after the transaction performing the rule action and vice versa.