Pass-through fields are response fields that you do not need for the current transformation but you might want to use later in the mapping.
For example you might only need the primary key from a source object for the Web Service transformation. However, you might want to use the other fields in the source object in a downstream transformation.
Incoming fields and response fields pass through the Web Services transformation to the success groups and fault group. However, when the mapping contains multiple sources, only the fields from the primary source pass through. The source that includes the primary key is the primary source. For example, in the following image, NewSource is the primary source and NewSource1 is the secondary source:
Because NewSource1 is a secondary source, fields from this source do not pass through to the success groups and fault group.
To determine the source of a field in the Success or Fault group, choose the