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Processes typically require data to function. For example,
data can be introduced to the process as input when the process
is initiated or at other activities in the process, and can be used
during the process as required. Data can also be provided as output
and returned to the process initiator when the process is complete.
Processes store data in variables that can be referenced and used
for making decisions, or acted on by services operations.
Variables can be used in two ways:
-
Process variables are used to store and access data at
run time. The data stored is expected to be different for each process
instance, and can be changed at run time. (See
Process variables
.)
-
Configuration parameters are used to set default data values
that apply to all process instances. The data cannot be changed
at run time, but can be configured using administration console
or Workbench. (See
Configuration parameters
.)
Process input and output data
You use process variables to specify
data that can be provided as input when processes are initiated.
Similarly, process variables can be used to store output data that
is returned to the process initiator when the process is complete.
You can also make it mandatory to provide input data when a process
is initiated.
The values of the General group of variable properties determine
whether a variable stores process input and output data. (See
Common variable properties
.)
Process data model
Data
that is saved for a process is represented internally as a data
tree. Each node in the data tree represents a data item that is
available to the process. The root node of the tree is named
process_data
.
Below this node are all other data nodes. The following standard
nodes are present for all processes:
-
create_time:
-
The date and time when the process instance was created.
-
creator_id:
-
The identification of the user who initiated the process
instance.
-
id:
-
The unique identifier for the process instance.
-
status:
-
The life cycle status of the process instance.
-
update_time:
-
The date and time when the process instance data last changed.
Any
other nodes below
process_data
represent data stored
in process variables that have been created for the process. The
following graphic illustrates the data tree for a process that has
three variables defined and named
booleanvar
,
stringvar
,
and
longvar
.
Variables
appear in alphabetical order in the data tree. The names of the
standard nodes are displayed using italics.
Simple variable
types, such as
boolean
and
long
,
are represented by leaf nodes in the data tree. Some variable types,
such as
xfaForm
and
xml
, have their
own data schema and are represented by nodes that have children.
The children nodes represent data that is organized according to
the variable’s schema.
Access to process data
You use process data for making decisions during process
execution, for providing input data to service operations, and for
saving service operation output data. Nodes in the data model can
be retrieved using XPath expressions. The data model of a process
can be viewed in XPath Builder, which is accessible from any view
or dialog box that allows you to express a property value as an XPath
expression.
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