The Service Builder allows you to redefine the OData services created in SAP Gateway Service Builder. Service can be redefined only if it is of type Service with SAP Annotations or Service with Vocabulary-Based Annotations.
The Redefine OData Service (SAP GW) function allows the user to do the following:
Redefine a service - to redefine a service for the first time in the Service Builder.
Extend the existing model - to add more artifacts to your model from an existing model. If your model already has artifacts from a reference model, you can add more artifacts from this model only.
Overwrite existing model - to overwrite the existing model in the Service Builder with a new model from a different service.
After choosing one of the redefine options (OData Service SAP GW, BW Query Service, SPI Service, OData Service), system allows you to select a service to redefine (you can select only those services that are registered in the current SAP Business Suite backend system ). Once you select a service, the model displays in tree view, allowing you to select the required artifacts (entity types, associations, function imports) for new model.
The Modification Generator enables you to make certain restricted changes in the service using an external framework like SAP Business Information Warehouse (BW), Service Provider Interface (SPI), and Generic Interaction Layer (GenIL). For example, these services might not have a proper label or might not need all the artifacts, in such cases, the Modification Generator allows you to make changes without influencing underlying Data Provider Class(DPC), and reuses existing model.
Two new DPC classes generate during the generation process. New DPC inherits DPC of the base service. As a result, the DPC methods of the base service is still available. New DPC extension class inherits the new DPC Base Class, enabling you to extend methods of your service.
In the new DPC extension class, you can change the behavior of the existing (original) service but you cannot change its interface.