1. Using SEGW (Service Gateway Builder) – Traditional Approach

• Transaction code: SEGW

• Steps:

  1. Create a new project in SEGW.

  2. Define Data Model (Entity Types & Entity Sets).

  3. Map Entities to ABAP structures/tables.

  4. Implement CRUD operations in DPC (Data Provider Class).

  5. Register and activate the service in /IWFND/MAINT_SERVICE.

• ✅ Use Case: Legacy SAP systems, custom OData for ECC or S/4HANA on-prem.

• ❌ Limitation: Manual coding, more effort, less aligned with modern RAP.

2. From ABAP CDS Views (Annotation-Based Exposure)

• Use annotation:

@OData.publish: true
define view entity Z_SalesOrder as select from I_SalesOrder { … }

• The CDS View is automatically published as an OData service.

• Then activate the service in /IWFND/MAINT_SERVICE.

• ✅ Use Case: Quick and simple OData exposure from CDS Views.

• ❌ Limitation: Only read-only services, no transactional behavior.

3. Using the RAP (RESTful ABAP Programming Model)

• RAP provides managed OData services with end-to-end support:

  1. Define CDS Data Model (Root & Projection Views).

  2. Define Behavior Definition (CRUD operations, determinations, validations).

  3. Create Service Definition to expose data.

  4. Create Service Binding (OData V2/V4) and publish.

• ✅ Use Case: Modern SAP S/4HANA Cloud / On-Prem for transactional + analytical apps.

• ❌ Limitation: Available only in S/4HANA and requires ABAP on Eclipse (ADT).

4. Using SAP Gateway Service Builder + RFC/BAPI

• Wrap an RFC or BAPI in SEGW to expose as OData.

• Often used in integration scenarios.

• ✅ Use Case: Exposing existing RFC/BAPIs as REST APIs.

• ❌ Limitation: Old-school approach, less future-proof.