Data Definition Include 
Data Definition Include
Definition
The data definition include contains the definitions of the internal tables and field strings used in the
import macro. Like the import macro, it is a further characteristic of the
cluster object. There is just one include for each cluster object, and it contains the definition of the data.
Use
The Interface Toolbox must recognize the structure of the cluster to be able to read cluster objects in the SAP System. The data definition include contains this structure definition. The Toolbox uses the data definition include to read the data from a cluster.
Activities
The Interface Toolbox enables you to generate a
data definition include automatically using the specifications for this program.