Create OData Services for CDS Views

This article shows how to use the SAP Gateway Builder to create OData services that support delta loads from CDS Views. The services can be consumed by Xtract Universal's ODP(OData) extraction type.

About Delta Support for CDS Views

Xtract Universal supports delta loads from CDS Views using the ODP(OData) extraction type. Delta loads require an OData V2 service created with SAP transaction SEGW. The service must be based on an ODP data source extractor or a delta enabled CDS View. There are other ways to create OData services based on CDS Views, but none of them create the required delta entities.

Enable Delta Load for CDS Views

To support delta loads, the CDS view requires the following ABAP annotations:

• @OData.publish: true
• @Analytics.dataExtraction.enabled: true
• @Analytics.dataExtraction.delta.changeDataCapture.automatic: true (delta fields must be defined manually if this annotation is missing)

The example code below shows how to use the annotations in CDS Views.

@AbapCatalog.viewEnhancementCategory: [#NONE]
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'Test CDS View'
@Metadata.ignorePropagatedAnnotations: true

" Ensure that the CDS View is found in the SAP OData V2 service catalog:
@OData.publish: true  

" Enable delta loads:
@Analytics.dataExtraction.enabled: true 

" Let SAP map delta fields automatically:
@Analytics.dataExtraction.delta.changeDataCapture.automatic: true 

" The example below tracks changes from tables MARA and MAKT:
define view entity ZMATERIAL_TEST as 
select from mara
left   outer to one join makt 
on     mara.matnr = makt.matnr
{
    key mara.matnr as MaterialNumber,
    mara.ersda as DateOfCreation,
    mara.created_at_time as TimeOfCreation,
    mara.ernam as MaterialName,
    mara.laeda as ModifiedDate,

    @Semantics.quantity.unitOfMeasure: 'WeightUnit'
    mara.brgew as BruttoWeight,

    @Semantics.quantity.unitOfMeasure: 'WeightUnit'
    mara.ntgew as NettoWeight,

    mara.gewei as WeightUnit,
    makt.spras as DescriptionLanguage,
    makt.maktx as Description
}

Create OData Services for CDS Views

Follow the steps below to create an OData service that can be used to extract delta loads from CDS Views. The service can be consumed by Xtract Universal's ODP(OData) extraction type.

Prerequisites

• SAP NetWeaver Gateway Release 2.0 Support Package 4 or higher. In SAP S/4HANA, the Gateway is embedded, but needs to be activated.
• SAP user with access to the SAP Gateway Service Builder.
• To extract data using the BW InfoProvider (ODP context BW), an open hub license is required.
• Optional: to transport services from one SAP system to another, e.g., from a test environment to a production environment, authorization for CTS (Change and Transport System) is required.

Workflow

The creation of OData services can be divided into the following phases:

Service Definition

To create a project that bundles all artifacts needed to develop a service:

1. Log in to the SAP GUI.
2. Go to transaction SEGW. The SAP Gateway Builder opens.
3. Click Create Project ().
4. Enter a name and description for the OData service.
   
5. In the field Project Type, select Service with SAP Annotations.
6. If you want to transport the service to another SAP system, define a transport package.
   Otherwise, enter $TMP (temporary objects).
7. Click Continue () to create the project.

The new project is listed in the main window of the SAP Gateway Builder.

Data Model Definition

To define the model the service is based on:

1. In the main window of the SAP Gateway Builder, select your project and navigate to the DataModel directory of the project.
2. Right-click the DataModel directory and select Redefine > ODP Extraction from the context menu.
   
   
3. In the field ODP Context, select ABAP Core Data Services.
4. In the field ODP Name, select your CDS View entity. To look up CDS Views with the sqlViewName annotation, enter the SQL name of the CDS View, see Look Up SQL Names of CDS Views. The depicted example uses ZMATERIAL_TEST$E.
5. Click [Add ODP] to add the CDS View to the data model.
   
6. Click Next to continue on to step 2 of the Wizard.
7. Fill out any missing information and click Next. The window "Create Object Directory Entry" opens.
8. If you want to transport the service to another SAP system, define a transport package. If not, click Save () to continue on to step 3 of the Wizard.
9. Use the file tree menu to select the following entities and artifacts for the service:
   • EntityOf defines the structure of your data. Select the fields you want to add to the service.
   • DeltaLinksOfEntity contains delta links required to retrieve only changes (new, updated, or deleted records) instead of fetching the entire dataset. Select all items to activate delta updates.
   • SubscribedToEntity checks whether a client is subscribed to delta changes. Select this artifact to activate delta updates.
   • TerminateDeltasForEntity allows the client to stop tracking delta changes. Select this artifact to clean up unnecessary delta subscriptions.
   • entityOf defines the relationship between entities in the OData service, e.g., it links the main entity (EntityOf) with its delta-tracking entity (DeltaLinksOfEntity).
10. Click Finish ().

The subdirectories of the DataModel directory now contain the selected entities and artifacts.

The service can now be consumed by Xtract Universal's OData extraction type.

Related Links

• Knowledge Base Article: Create OData Services using the SAP Gateway Builder
• SAP Documentation: Publishing CDS Views as SAP Gateway Services
• SAP Help: SAP Gateway Service Builder
• SAP Learning: Building OData Services with SAP Gateway
• SAP Help: ODP-Based Data Extraction via OData