To create an additional structure, proceed as follows:
Another dialog box appears where you must first choose to define either an additional table, an additional field, an additional structure or code.
Additional structures are actually additional fields with a non-scalar type of data. This data type must always be a (flat) structure from the ABAP Dictionary.
An additional structure must be assigned to a node of the data source in the same way as an additional field. However, you can find all individual fields from the additional structure in this node of the data source. So, additional structures offer a simple way of calculating more than one additional field at the same time.