Leveraging CDS Table Functions with Function Modules in SAP ABAP

 Introduction:

In today's digital age, businesses increasingly require real-time access to integrated data from various sources. SAP ABAP offers powerful tools like Core Data Services (CDS) and Function Modules to address this need. In this blog, we'll explore a real-time example of how to create a CDS table function that utilizes an ABAP function module with parameters to retrieve and enrich data from an external system, all without using ABAP Managed Database Procedures (AMDP).

Scenario: Employee Details Enrichment Consider an SAP system managing employee data with basic attributes such as Employee ID, First Name, Last Name, and Department. To provide a more comprehensive view of employees, we want to enrich this data with additional information such as Manager Name and Contact Number, which resides in an external HR system.

Solution Approach: To achieve this, we'll follow these steps:

Step 1: Create an ABAP Function Module Develop an ABAP function module, say Z_ENRICH_EMPLOYEE_DATA, that accepts employee_id as an input parameter and returns the manager_name and contact_number as output parameters. This function module will fetch the required details from the external HR system using web service calls or any other integration method.

Function Module Logic:

abap
FUNCTION Z_ENRICH_EMPLOYEE_DATA.
*"----------------------------------------------------------------------
*"*"Local Interface:
*"  IMPORTING
*"     VALUE(IV_EMPLOYEE_ID) TYPE  STRING
*"  EXPORTING
*"     VALUE(EV_MANAGER_NAME) TYPE  STRING
*"     VALUE(EV_CONTACT_NUMBER) TYPE  STRING
*"----------------------------------------------------------------------
  DATA: lt_employee_data TYPE TABLE OF zemployee_data,
        ls_employee_data TYPE zemployee_data.

  " Call external HR system or web service to fetch data for employee_id
  " In this example, we'll assume data is fetched from a custom table.
  SELECT manager_name contact_number
    INTO CORRESPONDING FIELDS OF TABLE lt_employee_data
    FROM zexternal_hr_data
    WHERE employee_id = iv_employee_id.

  " In case the data is found for the employee_id
  IF lines( lt_employee_data ) > 0.
    READ TABLE lt_employee_data INTO ls_employee_data INDEX 1.
    ev_manager_name = ls_employee_data-manager_name.
    ev_contact_number = ls_employee_data-contact_number.
  ENDIF.
ENDFUNCTION.

Step 2: Register Function Module as RFC-enabled Ensure that the function module Z_ENRICH_EMPLOYEE_DATA is registered as Remote-Enabled (RFC-enabled) to allow external access.

Step 3: Create a CDS Table Function Develop a CDS table function named Z_ENRICHED_EMPLOYEE_DATA with parameters client and employee_id. The output structure should include fields for client, employee_id, manager_name, and contact_number.

CDS Table Function Logic:

abap
@AbapCatalog.sqlViewName: 'Z_ENRICHED_EMPLOYEE_DATA'
@AccessControl #CHECK
define table function Z_Enriched_Employee_Data
  with parameters
  @DefaultClientHandling: #CLIENT
  client : abap.clnt,
  employee_id : char8
as select from dummy as d
{
  client,
  employee_id,
  manager_name,
  contact_number
};

Step 4: Implement CDS View Logic In the CDS view definition, use Open SQL expressions to call the function module Z_ENRICH_EMPLOYEE_DATA with the provided employee_id and retrieve the Manager Name and Contact Number. The CDS view should return the enriched employee data.

CDS View Logic:

abap
@AbapCatalog.sqlViewName: 'Z_ENRICHED_EMPLOYEE_DATA'
@AccessControl #CHECK
define view Z_Enriched_Employee_Data as select from dummy as d
left outer join @FunctionName: 'Z_ENRICH_EMPLOYEE_DATA'
  @Environment.systemField: #CLIENT
  client,
  @Environment.systemField: #CLIENT
  employee_id,
  manager_name,
  contact_number
from dummy as d;

Step 5: Activate and Test the CDS View Activate the CDS table function and view. Test the CDS view by running a query in the ABAP Development Tools or SAP GUI, passing different employee_id values to validate the real-time data enrichment.

Conclusion: By leveraging CDS table functions and ABAP function modules, businesses can seamlessly enrich their existing data with real-time information from external systems. This powerful integration approach allows for a unified view of employee data, supporting better decision-making and more efficient HR processes.

Benefits:

• Real-time Data Enrichment: Retrieve up-to-date information from external systems without compromising system performance.
• Simplified Development: Achieve data integration and enrichment with a straightforward approach, avoiding the complexities of AMDP.
• Reusability: CDS table functions can be reused across various applications and scenarios, enhancing code maintainability.

Closing Remarks: In this blog, we explored a real-time example of using CDS table functions with ABAP function modules to enrich employee data. This integration approach empowers businesses to access and utilize data seamlessly, facilitating better insights, improved decision-making, and enhanced efficiency in HR processes.