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Developing RAP Applications

Overview

The high-level diagram below illustrates the end-to-end development process using the ABAP RESTful Application Programming Model (RAP). This process starts from defining the data model using CDS entities. It then moves through behavior and service exposure layers. Finally, it culminates in a SAP Fiori elements UI. This approach enables rapid, metadata-driven enterprise application development.

                                                      [Database]
                                                          ↓
                                                     [CDS Entity]
                                                          ↓ 
                                             [Behavior Definition + Class]
                                                          ↓
                                                 [Service Definition]
                                                          ↓
                                                  [OData V4 Binding]
                                                          ↓
                                                [SAP Fiori Elements UI]

Before you can create an ABAP RAP application, you need to create the following artifacts:

  1. Package

    • A logical container used to organize development objects (CDS views, classes, services, etc.).
    • Helps with transport management and modular design.

  2. Database (DB) Tables

    • Physical tables in the ABAP Dictionary that persist data. In RAP or CAP, you define data models through CDS views that map to underlying tables.
    • Types of DB tables:
      • Transparent tables
      • Views and CDS views: These provide logical representations of DB tables.

  3. Source Code Library

    • Libraries that can be shared across packages or projects. They are collections of reusable ABAP code, such as:
      • Classes
      • Function groups
      • Interfaces

  4. Transactional UI Services

    • SAP Fiori apps or UI services that allow users to perform business transactions (create, update, delete). In RAP, they are created using service definitions and service bindings (OData V4).
    • It automatically supports:
      • Draft handling
      • Validation and determinations
      • Actions, such as approve or submit
    • It can be launched through:
      • SAP Fiori launchpad
      • SAP Build Work Zone
      • Integrated into SAP S/4HANA Fiori catalogs/groups

  5. Message Class

    • Used to define and manage standardized messages (errors, warnings, information). They are used in exception handling, UI messages, or API responses.
    • Example: ZMSG001, with entries like:
      • 001: Customer does not exist.
      • 002: Order has already been approved.

Let's look into it in detail:

Create a Package

Before creating the DB table, you need to create a package that holds all the application metadata.

  1. In ADT, go to the Project Explorer, right-click on the ZPARTNER software component package and choose New > ABAP Package.
  2. Maintain the required information:
    • Name: ZPRA_LOYALTYHUB
    • Description: Loyalty Hub: On-Stack Partner Reference Application
  3. Choose Next. The system asks for the application component. You can skip this if you don't know it.
  4. Choose Next. A dialog box requesting the transport request is displayed.
    • If there is an existing transport request, select that transport request and choose Finish.
    • If there is no existing transport request, choose Create New Request and enter a description, for example Loyalty Hub Application, and choose Finish.

Database Table

A database table is a structured object used to store persistent data in the underlying SAP HANA database, similar to how tables work in traditional ABAP on-premise systems but with some modern cloud-specific approaches.

A database table requires that the attributes are defined in the table. Each attribute requires a type, such as data types or domains, based on the requirements. Let's first explore how to define these attributes, followed by the process of creating the database table.

Domains

A domain is a data type definition used in the ABAP Dictionary to define the technical attributes (such as data type, length, and value range) of a field that is reused across multiple data elements or tables.

Create a Domain

  1. Select the package where the domain needs to be created in, for example ZPRA_LOYALTYHUB.

  2. Right-click on the package and choose New > Other ABAP Repository Object.

  3. Search for Domain and select it. Choose Next.

  4. Enter the following information:

    • Name: ZLH_GIFTCARD_STATUS
    • Description: Gift Card Status

  5. Choose Next and select a transport request (either a new or an existing one).

  6. Choose Finish.

  7. Select the domain to enter the FIXED values below:

    Fixed Values Description
    A Active
    I Inactive

  8. Additionally, set the Data Type as CHAR.

The ZLH_GIFTCARD_STATUS domain is created and can be used in data elements. Similarly, create other domains for the entire application. Here is the list of the domains used in the Loyalty Hub application.

Data Elements

A data element is a semantic layer of the data type definition in the ABAP Dictionary. It builds on top of a domain (or directly defines a type) and provides:

  1. Meaningful descriptions (short, medium, long text labels)
  2. Field labels for UI and metadata
  3. Connection to domain (for technical details)

Create a Data Element

  1. Select the package where the data element needs to be created, for example ZPRA_LOYALTYHUB.
  2. Right-click on Dictionary and choose New > Data Elements.
  3. Enter the following information:
    • Name: ZLH_CATEGORY_DESC
    • Description: Category Description
  4. Choose Next and select a transport request (either a new or an existing one).
  5. Choose Finish.
  6. Open the data element you've created and set the following values:

    • Category: Predefined Type

    • Data Type: CHAR

    • Field Labels: Category Description

The ZLH_CATEGORY_DESC data element is created and can be used in DB tables. Similarly, create other data elements for the entire application. Here is the list of the data elements used in the Loyalty Hub application.

Create Database Table

You need to create a DB table to store the membership, categories, transactions and gift card data.

Create Transaction Table

  1. Right-click on your ZPRA_LOYALTYHUB ABAP package and choose New > Other ABAP Repository Object.

  2. Search for database table, select it, and choose Next.

  3. Maintain the required information and choose Next.

    • Name: zlh_transactions
    • Description: Loyalty Hub Transactions

  4. Select a transport request and choose Finish to create the DB table.

  5. Provide code for zlh_transactions table.

  6. Save and activate the changes.

Similarly, create other tables for the entire application. Here is the list of the tables used in the Loyalty Hub application.

Source Code Library

Create Class

You need to create a class responsible for calculating loyalty points for a business partner, which will be used in different validation scenarios, including gift card creation and category upgrades

  1. Right-click your ZPRA_LOYALTYHUB ABAP package and select New > ABAP Class.

  2. Maintain the required information and choose Next.

    • Name: ZCL_LH_LOYALTY_POINTS
    • Description: Loyalty points calculation

  3. Select a transport request and choose Finish to create the class.

  4. Replace the template from source code.

  5. Save and Activate.

Create Interface

You need to create an interface that contains reusable constants, enabling consistent values across the application and reducing duplication.

  1. Right-click your ZPRA_LOYALTYHUB ABAP package and select New > ABAP Interface.

  2. Maintain the required information and choose Next.

    • Name: ZIF_LH_CONSTANTS
    • Description: Interface for loyalty hub constants

  3. Select a transport request and choose Finish to create the interface.

  4. Replace the template from source code.

  5. Save and Activate.

Core Data Services (CDS)

You need to create the root CDS entity that represents the business partner and exposes associations to the child entities. This view serves as the basis for behavior.

  1. In the Project Explorer, right‑click the package named ZPRA_LOYALTYHUB. Choose New > Other ABAP Repository Object.
  2. Search for Data Definition (CDS View Entity) and choose Next.
  3. Enter:
    • Name: ZLH_R_BusinessPartner
    • Description: Business Partner Details
    • Transport: choose the request used earlier
  4. Choose Finish to open the editor.
  5. Provide code for the cds.
  6. Save and Activate.

Similarly, create other root view entities for the other business objects: category, membership, transaction, and gift card. Here is the list of the root view entities used in the Loyalty Hub application.

Next, you need to create a projection view to adapt the root entity for UI/service consumption.

  1. In the Project Explorer, right‑click the package named ZPRA_LOYALTYHUB. Choose New > Other ABAP Repository Object.
  2. Search for Data Definition (CDS View Entity) and choose Next.
  3. Enter:
    • Name: ZLH_C_BusinessPartner
    • Description: Business Partner Details
    • Transport: choose the request used earlier
  4. Choose Finish to open the editor.
  5. Provide code for the cds.
  6. Save and Activate.

Similarly, create other projection views for the other business objects: category, membership, transaction, and gift card. Here is the list of the projection view entities used in the Loyalty Hub application.

Next, you need to create the Metadata Extension CDS to add UI annotations for the consumption view.
This keeps the CDS model clean while allowing to have the annotations controlling how fields appear in the SAP Fiori elements preview app in a separate node.

  1. In the Project Explorer, right‑click the package named ZPRA_LOYALTYHUB. Choose New > Other ABAP Repository Object.
  2. Search for Metadata Extension and select Next.
  3. Enter:
    • Name: ZLH_E_BUSINESSPARTNER
    • Description: Metadata Extension for Business Partner
    • Extends View: ZLH_C_BusinessPartner
  4. Choose Finish to open the editor.
  5. Add UI annotations for identification, line item, field groups, facets, and selection fields.
  6. Save and Activate.

Similarly, create metadata extension views for the other business objects: category, membership, transaction, and gift card. Here is the list of the metadata extension view entities used in the Loyalty Hub application.

Transactional UI Services

To visualize the application UI built on top of all configurations, you need to create certain artifacts. These artifacts control the behavior of the end-user application. You can define determinations, validations, actions, mandatory fields, and more for these artifacts using transactional services generation.

Behavior Definition (BDEF)

Define the business object behavior (operations, draft, actions, and child handling) for the root entity.

  1. In the Project Explorer, right-click the ZPRA_LOYALTYHUB package.
  2. Choose New > Other ABAP Repository Object.
  3. Search for Behavior Definition, select it, and choose Next.
  4. Select the CDS root entity ZLH_R_BusinessPartner.
  5. Maintain the following information:
    • Name: ZLH_R_BusinessPartner
    • Description: Behavior Definition for Business Partner
  6. Choose Next, select a transport request, and choose Finish.
  7. Replace the default template from source code.
  8. Save and activate the BDEF artifact.

Similarly, create other required BDEFs. Here is the list of the other BDEF used in the Loyalty Hub application.

Behavior Implementation Class

This ABAP class implements the behavior logic declared in the BDEF. It handles validations, determinations, actions, and feature control.

  1. Open the ZLH_R_BusinessPartner BDEF.
  2. Place the cursor on:
implementation in class ZCL_LH_BusinessPartner unique
  1. Press Ctrl + 1 (Quick Assist).
  2. Choose Create Class. The class will be created automatically under the same package ZPRA_LOYALTYHUB.
  3. Add custom logic that is provided here in Local Types.
  4. Save and activate the class.

Similarly, create other implementation classes required. Here is the list of the other implementation classes used in the Loyalty Hub application.

Additionally, you also have to create OData v4-based UI services using ADT.

Service Definition

A service definition makes CDS consumption views available to consumers, including OData services.

  1. Right‑click the ZPRA_LOYALTYHUB package.
  2. Choose New > Other ABAP Repository Object.
  3. Search for Service Definition and choose Next**.
  4. Maintain:
    • Name: ZLoyaltyHub_Manage_SD
    • Description: Service Definition for Loyalty Hub
  5. Choose Next, select a transport request, and choose Finish.
  6. Add the required CDS consumption views.
  7. Save and activate the service definition.

Service Binding (OData V4)

A service binding converts a service definition into an OData V4 endpoint. It also generates a SAP Fiori elements preview app.

  1. Right‑click the ZPRA_LOYALTYHUB package.
  2. Choose New > Other ABAP Repository Object.
  3. Search for Service Binding and choose Next.
  4. Maintain:
    • Name: ZLOYALTYHUB_MANAGE_SB
    • Description: OData V4 Binding for Loyalty Hub
    • Service Definition: ZLoyaltyHub_Manage_SD
    • Binding Type: OData V4 - UI
  5. Choose Next, select a transport request, and choose Finish.
  6. Save and activate the service binding.

Local Publishing and Testing

  1. Double-click on Service Binding and choose Publish.

Note

It takes some time to complete the publishing action. Once completed, select the entity set and choose Preview to view the UI and test the local changes. The app runs in Preview mode in a local system to test.

Message Class

Message classes are used to define and manage reusable error, warning, success, and information messages.
These messages are consumed in RAP behaviors, validations, and actions to notify users through the SAP Fiori UI.

  1. In the Project Explorer, right‑click the ZPRA_LOYALTYHUB package.
  2. Choose New > Other ABAP Repository Object.
  3. Search for Message Class and choose Next.
  4. Maintain the following:
    • Name: ZPRA_LOYALTYHUB
    • Description: Messages for Loyalty Hub Application
  5. Choose Next, select a transport request, and choose Finish.
  6. The message class editor opens. Add the required message numbers and texts.

7. Save and activate the message class.

Refer here for messages used in the Loyalty Hub app.

As the app runs locally, we can now proceed with how to develop the business logic.