In the Designer, you can create a mapping parameter in a mapplet or mapping. After you create a parameter, it appears in the Expression Editor. You can then use the parameter in any expression in the mapplet or mapping. You can also use parameters in a source qualifier filter, user-defined join, or extract override, and in the Expression Editor of reusable transformations.

Before you run a session, define the mapping parameter value in a parameter file for the session. Use any constant value. During the session, the Integration Service evaluates all references to the parameter to the specified value. If the parameter is not defined in the parameter file, the Integration Service uses the user-defined initial value for the parameter. If the initial value is not defined, the Integration Service uses a default value based on the datatype of the mapping parameter.

You can change the value of a mapping parameter between sessions by editing the parameter file or by changing the parameter file used by the session.

You might use a mapping parameter instead of a database lookup. For example, you want to perform calculations using monthly gross earnings. Instead of using a Lookup transformation to connect to a database table for that information, you can create a gross earnings mapping parameter and update its value in the parameter file each month to reflect current earnings.

You might also use a mapping parameter in conjunction with a session parameter to reuse a mapping and session. For example, you have transactional data from different states stored in the same table in different databases, and you want to perform the same calculations on all data, while changing the state sales tax accordingly. Instead of creating a separate mapping and session for each state, you can create one mapping with a sales tax mapping parameter and a session using a source database connection session parameter. You can then create a different parameter file for each state. Before running the session, you can change the parameter file the Integration Service uses by entering a different parameter file name from

pmcmd

or by editing the session in the Workflow Manager.

To use a mapping parameter, complete the following steps: