When we create an OData service using SEGW, SAP automatically creates ABAP classes in the background. These classes handle the main logic of how the service works. ABAP classes generated automatically which includes: Model Provider Class (MPC): Defines the data model, like entities and properties. Data Provider Class (DPC): Handles the actual logic, like read, create, update, delete operations. Each has a base class (MPC, DPC) and an extension class (MPC_EXT, DPC_EXT) where we add custom code.