For the Read operation, you have to map one data source input parameter to the key property of the related BAPI, BAPI_EPM_PRODUCT_GET_DETAIL, and the other parameters as output.
Expand Service Implementation folder, expand the entity set, for example ProductCollection, to be mapped, right click the operation, GetEntity (Read), and select Map to Data Source. The Map to Data Source dialog box displays.
In Target System, select Local, and in Data Source Attribute select Remote Function Calls, and in Name, enter BAPI_EPM_PRODUCT_GET_DETAIL
The Mapping Screen displays with the Read operation.
You can use the Propose Mapping button in the Mapping UI to obtain a mapping proposal, including the output structure, HEADERDATA. However, BAPI_EPM_PRODUCT_GET_DETAIL has a mandatory input parameter, PRODUCT_ID.
We must provide a mapping for the mandatory input parameter.
Click Insert Row in the Mapping. A new line is added to the table.
In the column, Entity Set Property of the empty row, press F4, and select the property ProductId.
Drag the parameter PRODUCT_ID from the Data source view on the right to the added property, ProductId.
Click Save. The mapping for the Read operation is now complete.
You have mapped the read operation.
To proceed to the next step, see Generating the Service.