Please see below:
1. How to run a single task in a workflow - Are you talking about the workflow containing only one mapping task and then triggering that workflow? - If yes, a workflow can be triggered in the following methods (the pre-requisite is that the workflow is deployed as an application to the DIS):
- Using the Scheduler Service in IDQ which will trigger the workflow at a specified time - please refer to: 516751
- Using the infacmd Command Line - wfs startWorkflow
- Using the Admin Console - Click on the Application containing the workflow on the DIS > Select the workflow and click on Start Workflow below the Actions option.
2. How to run a workflow from a particular task in IDQ - You can create a command task in a Workflow (say wf_1) and place a infacmd command wfs startworkflow to run wf_2 in the Command task.
This would ensure that the wf_2 is called from a Command Task in wf_1 - Command Task Overview
There is no task that is capable of calling a workflow in IDQ.