Parameters in Mappings
You can assign parameters to mapping properties, or you can create parameters for mapping objects.
When you define a mapping parameter, you can bind the mapping parameter to a transformation parameter. The mapping parameter value overrides the default parameter value in the transformation.
When you bind a mapping parameter to a transformation parameter, the parameters must be the same type. The mapping parameter name does not have to be the same as the transformation parameter name.
You can use a parameter set or a parameter file to set the mapping parameter values at run time. You cannot set reusable transformation, reusable mapplet, or reusable data source parameter values with a parameter set or parameter file. To change parameter values in reusable objects at run time, expose the parameter values as mapping parameters. Configure mapping parameters for the exposed values in the parameter set or parameter file.
Use one of the following methods to define mapping parameters:
- Define mapping parameters on the Parameters tab of the mapping Properties view
- On the mapping Parameters tab, you can manually enter each parameter name, the parameter attributes, and the default value. You can bind these parameters to transformation parameters whenever you add a transformation to the mapping. You can update the mapping parameters on the mapping Parameters tab. You can also view and access the parameter in the Outline view.
- Add mapping parameters from reusable transformation parameters
- After you add a transformation to a mapping, you can create a mapping parameter directly from the transformation Parameters tab. To create a mapping parameter from the transformation parameter, expose the transformation parameter as a mapping parameter. The Developer tool creates a mapping parameter that has the same name and type as the transformation parameter.
- Add parameters to a non-reusable transformation
- If you create a transformation in a mapping, the transformation is a non-reusable transformation. If you parameterize any of the transformation properties, you create mapping parameters instead of transformation parameters. The mapping parameters bind to the transformation parameters.
Parameter Instance Value
When you add a reusable transformation with parameters to a mapping, you can configure the instance value for each parameter in the transformation.
The instance value is the parameter value for a specific mapping. You can set the instance value to a default value, a specific value, or to a mapping parameter value.
A mapping parameter or a mapplet parameter can override the default value of the transformation parameter. Select a mapping parameter or a mapplet parameter and bind the parameter to the transformation parameter.
Set the instance value on the transformation Parameters tab in the Properties view.
Choose one of the following options for the Instance Value:
- Expose as mapping parameter
- Create a mapping parameter with the same attributes as the transformation parameter and bind the mapping parameter to the transformation parameter in the same step. If you click the Expose as Mapping Parameter button a second time, and the transformation parameter is already bound to mapping parameter, the Developer tool does not change the mapping parameter.
- Parameter
- Browse for and select a mapping parameter to bind to the transformation parameter. You can also create a mapping parameter and bind it to the transformation parameter. When you create the mapping parameter and bind it, you are performing the same task as the Expose As Mapping Parameter option. However, when you manually create the mapping parameter, you can configure a different name than the transformation parameter.
- Use default
- Use the default value from the transformation parameter. Skip binding a mapping parameter to the transformation parameter.
- Value
- Enter a default parameter value to use in the mapping. Skip binding a mapping parameter to the transformation parameter.