What is Business Process Modeling Notation

BPMN depicts these four element types for business process diagrams:

1. Flow objects: events, activities, gateways
2. Connecting objects: sequence flow, message flow, association
3. Swimlanes: pool or lane
4. Artifacts: data object, group, annotation

These are the individual elements and how they are used to define a business process:

Events

A trigger that starts, modifies or completes a process. Event types include message, timer, error, compensation, signal, cancel, escalation, link and others. They are shown by circles containing other symbols based on event type. They are classified as either “throwing” or “catching,” depending on their function.

Activity

A particular activity or task performed by a person or system. It’s shown by a rectangle with rounded corners. They can become more detailed with sub-processes, loops, compensations and multiple instances.

Gateway

Decision point that can adjust the path based on conditions or events. They are shown as diamonds. They can be exclusive or inclusive, parallel, complex, or based on data or events.

Sequence flow

Shows the order of activities to be performed. It is shown as a straight line with an arrow. It might show a conditional flow, or a default flow.

Message flow

Depicts messages that flow across “pools,” or organization boundaries such as departments. It shouldn’t connect events or activities within a pool. It is represented by a dashed line with a circle at the start and an arrow at the end.

Association

Shown with a dotted line, it associates an artifact or text to an event, activity or gateway.

Pool and swimlane

A pool represents major participants in a process. A different pool may be in a different company or department but still involved in the process. Swimlanes within a pool show the activities and flow for a certain role or participant, defining who is accountable for what parts of the process.

Artifact

Additional information that developers add to bring a necessary level of detail to the diagram. There are three types of artifacts: data object, group or annotation. A data object shows what data is necessary for an activity. A group shows a logical grouping of activities but doesn’t change the diagram’s flow. An annotation provides further explanation to a part of the diagram.