You can disable incoming fields to connect only the generated sequence in the output fields, NEXTVAL and CURRVAL, to one or more downstream transformations. When you disable incoming fields, you can't connect the Sequence transformation to upstream transformations.
When you disable incoming fields, at least one field from another transformation must be connected to the downstream transformation along with the Sequence transformation fields. For example, if the mapping contains a Sequence transformation and a Source transformation and the Sequence transformation is connected to a Target transformation, you must connect at least one field from the Source transformation to the Target transformation.
The following image shows a mapping where incoming fields are disabled in the Sequence transformation:
You can't disable incoming fields in advanced mode.