Linking Variables to a Transformer
When you map data to and from a transformer, you create links between the pipeline variables and the transformer. Keep the following points in mind when you create links between pipeline and transformer variables:
You must explicitly link pipeline variables to the input and output variables of a transformer.
Designer does not perform any implicit linking with transformers. Even if the pipeline variables have the same name and data type as the transformer variables, no implicit linking occurs.
Designer does not automatically add the output of a transformer to the pipeline. If you want the output of a transformer to appear in the pipeline, you need to explicitly link the output variable to a
Pipeline Out variable.
If you do not link any output variables or the transformer does not have any declared output variables, the transformer service will not run.
You can link a transformer output variable to more than one
Pipeline Out variable.
You can assign a value to a transformer input value using
on the Pipeline view toolbar.
To prevent the Pipeline view from becoming cluttered, the Pipeline view may not display all the links between the transformer and the pipeline variables. To view all the links, double-click the transformer or click
next to the transformer name.
Use the following procedure to link pipeline and transformer variables when the transformer is not expanded. If the transformer is expanded (that is, you can see all of the input and output variables for the transformer), you link variables just as you would for an INVOKE step.
To create a link between a pipeline variable and a transformer
1. To create a link between a Pipeline In variable and a transformer variable, do the following:
a. In Pipeline In, select the variable you want to use as input to the transformer and drag your mouse to the collapsed transformer. Designer displays the Link dialog box.
b. In the Link To list, select the transformer variable to which you want to link the Pipeline In variable.
In the Link Tolist, Designer displays the phrase “has already been chosen” next to variables that are already linked to other variables transformer.
2. To create a link between a transformer output variable and a Pipeline Out variable, do the following:
a. Select the collapsed transformer and drag your mouse to the variable in Pipeline Out to which you want to link the transformer variable. Designer displays the Link dialog box.
b. In the Link From list, select the transformer variable that you want to link to the selected Pipeline Out variable.