BPMN Flow Objects
The building blocks of BPMN are 'Flow objects'. which represents the concepts of being modeled. Flow elements refer to the elements, that form a complete process flow when connected are connected. Connectors that connect the flow elements are called connecting objects. Readers of the BPD follow the flow of elements to see, how a business process gets executed and completed.
Flow objects can be separated into three. They are events, activities, and gateways.
Events represent an event exist in a business process.
BPMN Start Event Symbol
The start event symbol signals the first step of a business process.
BPMN Intermediate Event Symbol
The intermediate event symbol represents any event that occurs between start and end events.
BPMN End Event Symbol
The end event symbol signals, the final step in a business process.
View detailed explanation of BPMN Event symbols
Activities describes, the kind of work that is being done in a particular process instance. There are four activity types, they are tasks, sub-processes, transactions, and call activities.
BPMN Task Symbol
A task is the most basic level of an activity, and further broken down cannot be done. For eg:-, a morning routine business process might involve, the task of 'turning on your computer'.
BPMN Sub-Process Symbol
A sub-process is a group of tasks that fit together well. There are two different views of sub-process. One is the 'collapsed view', that has an expandable plus sign, to show 'more details'. The other view is an 'expanded sub-process view', which is large enough to house, all the tasks that describe the sub-process fully.
BPMN Transaction Symbol
It is a specialized sub-process that involves payment.
BPMN Call Symbol
It is a global sub-process, that is being reused at various points in the business flow.
Gateways are symbols, that separate and recombine flows in a BPMN diagram. There are different types of gateways:
BPMN Exclusive Symbol
Exclusive - evaluates the state of business process and, based on the condition, breaks the flow into one or more mutually exclusive paths. For eg:-, one report will be written only, if a supervisor grants approval; no report will be generated, if the supervisor withholds approval.
BPMN Event-Based Symbol
Event-based - an event-based gateway is similar to the exclusive gateway. Both involve one path in the process flow. In the case of an 'event-based gateway', you were evaluating, which event has occurred, and not which condition is being met. For eg:-, you might wait to send an email, until the CEO has arrived at the office. So if the CEO doesn’t arrive to the office, the email will remain unsent.
BPMN Parallel Symbol
Parallel - differs from other gateways because it’s not dependent on events or conditions. Instead, parallel gateways were used to represent two concurrent tasks in a business flow. An example is a marketing department that generates new sales leads and contacts the existing leads at the same time.
BPMN Inclusive Symbol
Inclusive - breaks the business process flow into one or more flows. For example, an inclusive gateway could involve business actions taken based on survey results. One process may be triggered, if the consumer is satisfied with Product X. Another flow is triggered when the consumer indicates that they are satisfied with product Y, and a third process is triggered, if they aren't satisfied with X.
BPMN Exclusive Event-Based Symbol
Exclusive event-based - starts a new process instance, with each occurrence of a subsequent event.
BPMN Complex Symbol
Complex - these gateways are only used for the most complex flows in a business process. When you need multiple gateways to describe the business flow, is an ideal use case for the complex gateway.
BPMN Parallel Event-Based Symbol
Parallel event-based - as the name suggests, this gateway is similar to parallel gateway. It allows for multiple processes to happen at the same time, but unlike the parallel gateway, processes are event-dependent.
Hope this helps!