If you use an OR rule, several possible branches of the process can be executed. However, at least one branch must be executed.
This type of pattern starts with a function that represents a decision and is followed by an OR rule. The rule is followed by several branches, each of which starts with an event.
You can define conditions that have their own business semantics and specify which branch is to be taken after the OR. The conditions can be specified as follows:
The Condition expression attribute is specified at the connection leading from the OR rule to the subsequent event.
The Connection role attribute is specified at the connection leading from the OR rule to the subsequent event.
The Name attribute is specified for the event that follows the OR rule.
In the BPMN diagram, the joining OR pattern is transformed into a task that requires a decision and is followed by a data-based OR gateway. Branches that only contain events are grouped together in a single branch in the BPMN diagram. The conditions are combined in such a way that each condition generates a separate line in the Condition expression attribute of the connection.
The Condition expression attribute specified in the EPC (see graphic) is transformed into the Condition expression attribute of the connection that starts at the OR gateway. The graphic displays the exact mapping of this type of pattern.
The graphic displays an example with two branches, but any number of branches can be modeled.