You define the fields to be transferred together with their properties.
If you have created the open hub destination based on a template, you will be offered all fields from the template as fields for the open hub destination. You can edit the field list by removing or adding fields. You can also change the properties of these fields.
If the template for the open hub destination is a DataSource, the field SOURSYSTEM is automatically added to the field list with reference to InfoObject 0SOURSYSTEM. This field is required if data from heterogeneous source systems is being written to the same database table. The data transfer process inserts the source system ID that is relevant for the connected DataSource. You can delete this field if it is not needed.
If you have selected Database Table as the destination and Semantic Key as the property, the field list is given an additional column. You can define the key fields for the semantic key here.