When you import a target definition with a composite key, you need to build a unique key from the source composite key using the appropriate transformations. You need to connect this unique key to the GPK of the corresponding group of target definition.

The following figure shows an example of a mapping that uses an Expression transformation to create a unique key from the composite key:

In this example, the PARTY_ORIG_SYSTEM column and the PARTY_ORIG_SYSTEM_REFERENCE column build a composite key. An Expression transformation generates a unique key. This unique key is linked to primary key of the target definition.