When you add a Mapping task to a workflow, you select a single mapping for the task to run. You can select any mapping that has physical data objects as input and output. When you change the mapping, the Model Repository Service tracks the effects of these changes on all Mapping tasks that include the mapping.
When you run a workflow, the workflow passes input data to a Mapping task in parameters and variables. The Mapping task uses the input data to run the mapping. When the task finishes running the mapping, the Mapping task passes output data back to the workflow in variables.