Map input ports to the keys in the operation output. Any port that you map to a key must be a string, integer, or bigint datatype. Map data to the keys in all levels in the operation output above the hierarchy level that you are including in the SOAP message. Include the foreign keys for all levels above and including the level you are mapping.
You do not have to map input ports to keys if you are mapping only the lowest level of the operation output hierarchy.