Structure of a Delta Query Enabled OData Service
An OData service in NetWeaver Gateway consists of two ABAP classes: the model provider class and the data provider class. The classes are maintained in the Gateway ABAP system either through Object Navigator (transaction SE80) or through Service Builder (transaction SEGW).
Model Provider Class
The model provider class defines the data model for the service, specifying the entities and entity sets that are managed by the service. The abstract class for a model provider class is ODC IWBEP~CL_MGW_ABS_MODEL. Every concrete implementation of a Model Provider Class must be derived from this class. In general, the model provider class does not require any modifications to enhance a service into providing delta query support.
Data Provider Class
The data provider class defines what happens when the service executes. The class contains the business logic behind the create, read, update, and delete (CRUD) operations performed by the service on the entities and entity sets defined in the model. The class contains the GET_ENTITYSET and GET_ENTITYSET_DELTA methods, which are both used in implementing delta queries. You must create or redefine these methods for a service to enable it to handle delta queries.