Modelling and documenting processes with BPMN
A graphical notation such as the event-driven process chain (EPC) or Business Process Model and Notation (BPMN) is used to model and document processes.
History
The first graphical notations were created as early as 1921, and over the years various flowcharts and diagrams have appeared to depict processes. In 2002, IBM finally published the BPMN concept. The aim was to standardize the various forms of representation. Today, the further development of BPMN 2.0 is used. It has also been an ISO standard since December 2013 (ISO/IEC 19510:2013).
BPMN 2.0
The Business Process Model and Notation comprises over 150 different symbols. These symbols belong to different categories and there are therefore many ways to visualize a process. When using BPMN, it is therefore essential to define company-wide standards for the modelling of processes using so-called modelling conventions. This limits the number of symbols. There are also rules in BPMN that allow different variants of handling. Internal modelling conventions are limited to a standard. This ensures that every employee can read and understand the process representations.
We present the most important symbols below. You can also download the Signavio overview poster free of charge.
Important symbols
There are four superordinate categories for all graphical BPMN symbols:
- Flow Objects are the elementary building blocks of BPMN.
- Connecting Objects are used to connect all elements.
- Artefacts are used to promote the overview or understanding of a process but do not change the flow or function of the process.
- Swimlanes or pools represent different process participants.
1. Flow Objects
Activities
Task: The most common of all activities is the task. It describes the various tasks within a process and is linked with so-called sequence flows to form a chain.
Sub-process: A sub-process can be used to summarize a section or sub-process within a process. This helps to maintain an overview so that various levels of detail can be achieved if very large and complex processes need to be displayed.
Call activity: A call activity works similarly to a sub-process and is visually a task with a wider border. The difference to a sub-process is that the process is not directly defined locally but is called via a link. This means that a sub-process that is required in many processes can be defined externally and linked. The sub-process can then be changed as required without interfering with any of the other processes.
Gateaways
XOR: The XOR (exclusive “or”) gateway can be seen as an ‘either-or decision’. Exactly one of all outgoing sequence flows is selected.
OR: The OR (inclusive “or”) gateway selects at least one outgoing sequence flow, but can also select several, depending on the situation.
AND: With the AND gateway, all possible outgoing sequence flows are executed simultaneously.
Event-based: The event-based gateway has various outputs and each of these outputs is linked to an event such as ‘10 minutes elapsed’ or ‘e-mail received’. The event that occurs first is selected and the process then continues via this sequence flow.
Complex conditional: Any decisions can be defined in writing at the outputs of a complex gateway. It is used if the decision cannot be represented by a simple gateway because the continuation of the process is subject to several conditions.
Events
Start event: The start event defines the beginning of the process and must therefore occur at least once in each process. It is represented by a simple circle. The start event can be triggered by various circumstances. For example, the receipt of a message.
Intermediate event: An intermediate event is in the middle of the process and can trigger certain reactions. It is shown with a double border line and can fulfil many different functions. For example, it can trigger certain tasks with a simple timer or intercept an error.
2. Connecting Objects
Sequence flow: The sequence flow marks the sequence and connections between the flow objects within the process.
Message flow: The message flow also connects various flow objects or swimlanes (category 4) and thus indicates the communication between the various process participants.
Association: The association connects artefacts with the flow objects and thus shows the relationship between the various elements. The association can be directed or undirected.
3. Artefacts
Comment: A comment can be attached to almost any element and can store additional information or important notes. It can also be used to comment on the process so that it cannot be misunderstood in the future or by outsiders.
Group: A group can visually summarize a part of the process, allowing it to be subdivided and labelled. The group should not be confused with a sub-process. This looks similar, but has a solid line and not just a visual function.
Data object: The data object can be connected to various flow objects using the association (Connecting Object) to display a data flow or assign documents. It is also useful to add the status of the document at each step to provide an overview and clarity regarding which process is taking place where. Alternatively, the message symbol can also be used for messages.
Data memory: The data memory is used to represent a database or something similar. It is also linked to an association and indicates, for example, whether a flow object is accessing a database.
4. Swimlanes
Pool: Pools are used to model different process participants. Typically, process participants are organizations or customers. It is important that the different pools do not have a major influence on each other, but that they all participate in the same process. Each pool belongs to a process participant. The message flow (category 2) is used between the pools to represent communication. As the participants are independent of each other and the parts of the process cannot be defined, a normal sequence flow cannot be used. For example, when processing an order, several messages or files can arrive from a customer or supplier, which are used in the process. This means that process participants can be involved without knowing this part of the process.
Swimlanes: A swimlane is, so to speak, a lane in the pool of a process participant. The swimlane divides the organization, which is represented as a pool, into lanes for each role within the organization.
Example processes:
Would you like to learn the BPMN language?
Get in touch with us!
