Something that happens
Introduction to the notion
The event is a unit of exchange within the system. The event lets us know that something has happened. This category of representation already appears in the semantic aspect. It is extremely helpful too in the pragmatic aspect as it enables the communication between the actors and the activities to be studied. As with the objects, the modeler must be able to distinguish the events according to their type. The rule is as follows:
- External events that inform the Enterprise System are, by default, semantic in nature. (The events linked to “red tape” will be excluded: they are external but are in no way semantic or essential. Rather, they are more down to organizational aberrations, which can be seen in all sectors of activity, and which are targeted by the modernization of the public sector.)
- Internal events, between enterprise processes or between functions, are pragmatic in nature.
The organized process diagram can mix both types of events. All events carry information. A better explanation would be that the notion of event has two facets:
- The event signals: as long as it expresses that something significant has happened in the environment, the event is seen as a signal to which the system can reply (the signal can trigger reactions from the system).
- The event informs: it provides information about what has happened, the modified object, change in the internal state, the emitters (actors involved), etc.; in this way, the event conveys a message.
The information conveyed by the message is the same as that of the objects. For all that, it is different from it because it is only the reflection, a trace or an extract taken at a certain moment in the life of the object. What is communicated between the emitter and the receiver of the message is not the object itself, but this photo taken at one moment in time. These slight differences count a great deal in avoiding any confusion in the modeling.
This definition is voluntarily very general and close to the ordinary perception. In no way does it try to reproduce the complexity or the contributions made by technology around this notion. Our starting point must always be the reality in its raw state, before it is conditioned – informed – by our practices. As with “activity”, “event” designates a common and very general notion. The methodology has to accept it as is.
Related term: signal.