What is BPMN?

BPMN

Business process modeling notation is a technique for modeling business processes in software engineering. We use it to represent business processes as diagrams to help in their optimization.

Components of BPMN

A BPMN diagram consists of the following core components:

Activity

An activity is a unit of a business process representing a work task. Activities are drawn as rectangles with rounded edges.

Event

An event can be of the following three types.

• Start event: It triggers the start of the business process.

• End event: It indicates that the business process has concluded.

• Intermediate event: It is an event that occurs between the start and end event.

Gateway

An activity can often be split into several activities, which later join together to continue the process. This forking and merging of activities are represented through gateways. We've got the following types of gateways:

• OR gateway: When an OR gateway is encountered, the business process continues after completing one or more forked activities.

• AND gateway: An AND gateway is used when all split activities must be performed for the process to resume.

• XOR gateway: A XOR gateway proceeds only when exactly one of the branches is completed.

Sequence flow

Activities in BPMN occur sequentially. This sequence flow is represented by using arrows between subsequent activities.

Pools and lanes

In BPMN, pools, and lanes indicate roles, that is, who performs which activity. Pools represent a whole organization or group. Pool lanes depict organizational actors, such as departments, internal roles, and software systems.

Note: If we want to represent an external organization whose activities and processes we do not know of, we can make a simple rectangle as a pool, known as a black-box pool.

Message flow

Message flows represent the flow of information between pools. A message flow proceeds from the activity and goes to either the boundary of a pool or an activity in another pool. The message holds information that triggers activities in the other pool.

Example

Let's understand BPMN using a simple example. Suppose we've to make a BPMN diagram of the order-to-cash process of an organization. The process starts when a purchase order is received. The purchase order is confirmed or rejected after verifying the availability of the items requested. In case of order confirmation, an invoice is generated, and the requested goods are shipped. The process is ended when the order is archived. The BPMN diagram for this scenario is modeled below.