Workflow data objects (see Workflow Data Objects) are the workflow engines data store. Some of the attributes on the specified workflow data objects are populated when the process is enacted. It is useful, however, to update or set the values of workflow data object attributes as the workflow process is executed. To support this, some activity types can map data back into the workflow engine. This is particularly useful for automatic activities as the business methods they invoke could conceivably access data stored on any entity in the application and return it for use in subsequent activities in the workflow process. These return mappings from a business process object method associated with an automatic activity are optional.