Events?

External event- an event that occurs outside the system, usually initiated by an external agent or actor.
• Agent (actor) or organisational unit that supplies/receives data from the system
• Customer- order/return
• Must be defined clearly by its name (event name). Description should include the action that the external agent wants to pursue
e.g.) customer places an order – this title of an event describes the external agent (customer in this case) and the action that the customer wants to take (place an order for product).


Temporal event- an event that occurs as a result of reaching a point in time
• Generated by system automatically
e.g.) payroll or store statistics reports (end of day stats/footfall etc.)
• No agent/actor required to make demands, system generates outputs when they are needed periodically
e.g.) internal outputs needed include....management reports, operational reports, internal statements and documents
external outputs needed...statements, status reports, bills, reminders and quotes


State event- an event that occurs when something happens inside the system that triggers the need for processing. Also called internal events.
e.g.) stock falls below minimum stock level (reorder level) so the system initiates prompt to reorder or reorders automatically