For each business process definition (BPD) or service that
you create, you must declare variables to capture the business data
that activities in that BPD or steps in that service use.
Before you begin
If you are declaring variables for a BPD, open the
IBM® Process
Designer desktop editor.
About this task
You can add the following variables to your BPDs:
Table 1. Variables available for addition to business process definitionsVariable |
Description |
Private |
Local variables that are used only within the
process. |
Input |
Variable that represents input data passed to
the current BPD or service. |
Output |
Variable that represents output data that the
current BPD or service returns to its caller. |
Exposed process variable (EPV) |
Special type of variables that you can create
to set or alter values while instances of a process are running. |
Only
BPD variables that are marked as process instance identifiers can
be used for instance-based correlation of intermediate message events
that use the SCA triggering mechanism. A process instance identifier
variable can be a private, input, or output variable, and can be a
simple or complex variable type.
Procedure
If you want to add an exposed process variable, click Link EPV, and then select the EPV from the list. If you
want to add a private, input, or output variable, complete the following
steps:
- Open your BPD or service diagram in Process Designer.
- In the Variables tab, click Add Private, Add Input, or Add Output to create the corresponding variable.
Note: If an input variable is a complex
type and you are passing it from a BPD to a service, it will be passed
as a value. If you want the updated value to be returned, also declare
it as an output variable. If the complex type is a shared business
object, you do not need to return it as an output because the updates
that are made in a service will become visible to everyone who uses
the shared business object.
- In the Details section:
- Type a variable name in the Name field.
Note: Variable names start with a lowercase letter,
with subsequent words capitalized, for example: myVar. Do not use underscores or spaces in variable names. Variable names
are case-sensitive.
- Click Select next to the Variable Type field to select the type of the variable. Custom business objects that you created are also listed.
- Optional: Type a description of the variable
in the Documentation field.
- Optional: If you want your variable to be
an array, select Is List.
- Optional: To set a default value for the variable,
in the Default Value section, select Has Default, and enter the value in the corresponding
field.
- Optional: To include the BPD variable in the
business data that users can view in Process Portal, in
the Business Data section, select Visible in Process Portal, and type an alias in the Alias field.
Tip: The search alias
must be unique to the variable type throughout the process server
on which the BPD runs. If a variable is used in parent and nested
processes, use the same search alias if you want search results to
include all related processes.
- Optional: To include the BPD variable values
in the data that is collected and used to create reports, in the Performance Tracking section, select Track
this Field.
- To declare a BPD variable as a secondary process identifier,
you must mark it as a process instance identifier. In the Process Identification section, select Variable
is used as Process Instance Identifier. While it is possible
to mark any variable as process instance identifier, it is advisable
to use a variable for this purpose that is not too complex.
Important: The value that is written to the variable must be
unique for each instance of the BPD. Because variables that are selected
as process instance identifiers can be written to only once, be careful
during initialization, data mapping, pre-assignments, and post-assignments
to avoid it ever being written to twice for an instance. Writing any
value to such a variable more than once causes an error.
Tip: If you clear the selection for a variable that is already
used for correlation, the variable is marked with an error icon on
the Data Mapping tab.
Variables that are marked as process instance identifiers can be
selected to be used for correlation, and are indicated in variable
selection dialogs by the text [Identifier].
- To save the configuration, click Save in the main toolbar.
What to do next
The BPD or service includes variables that can be passed
to activities or services, by mapping input and output variables.
If you have a coach in the diagram, the variables are directly available
inside the diagram, and can be dragged in the layout window.