Designing processes - EMC Community Network

Designing the Process
instance. To make this match, the request message has to include some data that uniquely identifies the
requesting process instance. This is called the correlation identifier. The response message coming
from the service also contains the same correlation identifier, so that when the Process Integrator
receives the incoming message, it reads the correlation identifier and then routes the message to the
right process instance.
There are two basic approaches to specify a correlation identifier:
• Transport-based
• Content-based
In the transport-based approach, the identifier is created as part of the protocol control field. For
example, a Java Message Service (JMS) message can generate a unique key that can be used to
identify the process instance.
In the content-based approach, the identifier is taken from the payload. For example, in a purchase
order application, the purchase order number is unique to each process instance. Therefore, it can be
used to match the response to the requesting process instance. In some situations you need to combine
multiple data fields to ensure uniqueness.
If a correlation identifier has not been configured for an activity or if it is missing from the incoming
message, the system looks for a correlation set to match the message to a workflow. Correlation
sets are specified at the process level in the Advanced tab of the Process Properties. They are used
to enable correlation in the activities of that process. You can use one or more process variables to
create a correlation set to uniquely identify the process instance.
Use the data mapper’s copy function to compare one of the attributes of your incoming data to the
value of one of your process variables belonging to a correlation set.
Note: The copy function is used to compare these values. If there is a match between the value of
the process variable (belonging to a correlation set) and the value of a data attribute of the incoming
message, the match is successful and the step activity is completed.
Using the data mapper
The data mapper is a graphical tool that simplifies the exchange of process data, such as workflow
method arguments, web services parameters, return values from database queries, and attributes
specific to services such as JMS, HTTP, or FTP. This section addresses several topics involving the use
of the data mapper that can arise in your projects.
Mapping repeating attributes
There are times that you need to copy a source variable to multiple target variables. This can be done
using the data mapper. You can also perform operations in the course of the mapping, for example,
mapping a date to a date and also mapping the date to a string variable (using the date-to-string
function) at the same time.
To copy one variable to many variables:
1. Create the copy function as usual for the first item.
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