{"id":7671,"date":"2025-08-27T15:36:50","date_gmt":"2025-08-27T10:06:50","guid":{"rendered":"https:\/\/www.sapewmhelp.com\/?question=how-to-create-a-web-api-using-custom-entity"},"modified":"2025-08-27T15:36:50","modified_gmt":"2025-08-27T10:06:50","slug":"how-to-create-a-web-api-using-custom-entity","status":"publish","type":"question","link":"https:\/\/www.sapewmhelp.com\/?question=how-to-create-a-web-api-using-custom-entity","title":{"rendered":"How to create a web api using custom entity"},"content":{"rendered":"

A Custom Entity<\/strong> in RAP is like a virtual data model<\/strong> \u2014 it does not persist data in a DB table<\/strong>, but fetches it from logic (e.g., CDS views, APIs, function modules, or custom code).<\/p>\n

It is exposed via a behavior definition<\/strong> and then published as an OData\/Web API service<\/strong>.<\/p>\n<\/p>\n

1. Create a Custom Entity in CDS<\/strong><\/p>\n

@EndUserText.label: ‘Custom Employee API Entity’
\ndefine custom entity ZC_EMPLOYEE_API {
\nkey empid : abap.char(10);
\nempname : abap.char(40);
\ndepartment: abap.char(20);
\n}<\/p>\n<\/p>\n

2. Define a Behavior Implementation (Handler Class)<\/strong><\/p>\n

CLASS zcl_employee_handler DEFINITION
\nPUBLIC FINAL CREATE PUBLIC.
\nPUBLIC SECTION.
\nINTERFACES if_rap_query_provider.
\nENDCLASS.<\/p>\n

CLASS zcl_employee_handler IMPLEMENTATION.
\nMETHOD if_rap_query_provider~select.
\nDATA lt_data TYPE TABLE OF zc_employee_api.<\/p>\n

“Fetch data (from table, FM, RFC, etc.)
\nSELECT empid, empname, dept AS department
\nFROM zemployees
\nINTO TABLE @lt_data.<\/p>\n

“Return data
\nresult = CORRESPONDING #( lt_data ).
\nENDMETHOD.
\nENDCLASS.<\/p>\n

 <\/p>\n

3. Register Service in Service Definition<\/strong><\/p>\n

@EndUserText.label: ‘Employee API Service’
\ndefine service ZUI_EMPLOYEE_API {
\nexpose ZC_EMPLOYEE_API;
\n}<\/p>\n

 <\/p>\n

4. Publish via Service Binding<\/strong><\/p>\n