4.0

What to do next
The elements are joined, but you have not defined the data flow. You must define the IN and OUT bindings
to bind incoming and outgoing data to workflow attributes.
Data Flow of a Workflow
The data flow of a workflow is the manner in which workflow element input and output parameters bind to
workflow attributes as each element of the workflow runs. You define the data flow of a workflow by using
schema element bindings.
When an element in the workflow schema runs, it requires data in the form of input parameters. It takes the
data for its input parameters by binding to a workflow attribute that you set when you create the workflow,
or by binding to an attribute that a preceding element in the workflow set when it ran.
The element processes the data, possibly transforms it, and generates the results of its run in the form of output
parameters. The element binds its resulting output parameters to new workflow attributes that it creates. Other
elements in the schema can bind to these new workflow attributes as their input parameters. The workflow
can generate the attributes as its output parameters at the end of its run.
Figure 2-2 shows a very simple workflow. The black arrows represent the element linking and the logical flow
of the workflow. The red lines show the data flow of the workflow.
Figure 2-2. Example of Workflow Data Flow
The data flows through the workflow as follows.
1 The workflow starts with input parameters a and b.
2 The first element processes parameter a and binds the result of the processing to workflow attribute c.
3 The first element processes parameter b and binds the result of the processing to workflow attribute d.
4 The second element takes workflow attribute c as an input parameter, processes it, and binds the resulting
output parameter to workflow attribute e.
5 The second element takes workflow attribute d as an input parameter, processes it, and generates output
parameter f.
6 The workflow ends and generates workflow attribute f as its output parameter, the result of its run.
Chapter 2 Developing Workflows
VMware, Inc. 33