2011

■ Logical commands (such as If/Else and For Each)
■ Workflow structure commands (such as Parallel, Sequence, and Prompt
User).
For information about the available activities, see Workflow Activity Input
dialog boxes
(page 2025).
Parallel and Sequence Activities
In a workflow, parallel activities are independent of one another. For example,
when connecting to two data stores, parallel connections ensure that the
second connection executes even if the first one fails.
A sequence activity depends on previous activities. For example, within the
parallel activity at the top of the overlay workflow are two sets of sequence
activities. Each one connects to a particular data store and then creates a layer
for that data store. If the connection fails, the layer cannot be created.
Setting Activity Parameters
Each workflow activity has a set of parameters. Optionally, you can set default
parameters and specify that the workflow display a prompt at run-time. The
person running the workflow can then substitute other values. For example,
you can set default data stores for an overlay, but allow others to substitute
different data stores when they run the workflow.
Some parameters are required. For example, a Connect To Data Store activity
requires the name of the provider and the location of the data store to connect
to. Some parameters are optional, for example, the Display Name for the
activity. All optional parameters have default values you can change.
NOTE Although Display Name is optional, it is a good idea to name all activities.
If activities are not named, you can confuse them when you bind a parameter of
one activity to the output of a previous one. See the following section.
Binding Parameters
Often, a sequence activity is bound to a preceding activity. When you bind an
activity, you set its parameter to be the result of a previous activity. For
example, you can use the output of an activity that creates a layer as the source
layer for a subsequent overlay operation.
282 | Chapter 2 Setting Up