When you use a dynamic lookup cache, map incoming fields with lookup cache fields on the
Field Mapping
tab. The
Field Mapping
tab is only available when you configure the Lookup transformation to use a dynamic cache.
You must map all of the incoming fields when you use a dynamic cache so that the cache can update as the task runs. Optionally, you can map the Sequence-ID field instead of an incoming field if you want to create a generated key for a field in the target object.