A logical data object can have a Read mapping and a Write mapping. A Read or Write mapping can contain transformations that use parameters. You can bind the reusable transformation parameters to parameters in the Read or Write mapping.

For example, a logical data object has a Read mapping that contains an Expression transformation. The Expression transformation has a parameter that defines a decimal value in an expression. The default value is 100.

When you add the Expression transformation to the Read mapping, you might want to use a different parameter value. You can create a parameter at the Read mapping level to override the transformation parameter. Click

Expose as Mapping Parameter

to create a duplicate parameter in the Read mapping. The Developer tool binds the duplicate parameter to the transformation parameter.

The following image shows the

Parameters

tab for the Expression transformation in the Read mapping:

To view the duplicate parameter, select the logical data object in the Outline view. You can change the parameter default value at the Read mapping level.

When you add the logical data object to a mapplet or mapping, you can override the Read mapping parameter. Create a duplicate parameter in the mapplet or the mapping. Change the default value of the duplicate parameter.