Field types
Reports distinguishes three conceptual types of fields that can be included in reports:
• Normal fields
Normal fields are immediately available and selectable for a report definition, belonging to the active business object.
• Reference fields
Reference fields have a one-to-one relationship with the main business object in the report definition. For example, a property can only be located in one city.
• Association fields
Association fields have a one-to-many relationship with the main business object in the report definition. For example, multiple orders may be linked to a single property.
System fields, however, are still just fields on a business object. As long as a system field is exposed in the selection step you are reporting on and it is allowed to be used (In selection), then they can be added as fields in a report definition.