METHOD salesorderset_get_entityset. 
SELECT * FROM zsch15_so
INTO CORRESPONDING FIELDS OF TABLE @et_entityset. 
ENDMETHOD.
METHOD salesorderset_get_entity. 
DATA(lv_id) = VALUE #( it_key_tab[ name = 'SalesOrderID' ]-value OPTIONAL ). 
SELECT SINGLE * FROM zsch15_so
WHERE sales_order_id = @lv_id
INTO CORRESPONDING FIELDS OF @er_entity.
IF sy-subrc <> 0.
RAISE EXCEPTION TYPE /iwbep/cx_mgw_busi_exception
EXPORTING
textid = /iwbep/cx_mgw_busi_exception=>resource_not_found. 
ENDIF.
ENDMETHOD.

METHOD lineitemset_get_entityset. 
DATA(lt_keys) = io_tech_request_context->get_source_keys( ). 
DATA(lv_id) = VALUE #( lt_keys[ name = 'SalesOrderID' ]-value
OPTIONAL ).
IF lv_id IS INITIAL. 
SELECT * FROM zsch15_soi
INTO CORRESPONDING FIELDS OF TABLE @et_entityset.
ELSE.
SELECT * FROM zsch15_soi
WHERE sales_order_id = @lv_id
INTO CORRESPONDING FIELDS OF TABLE @et_entityset.
ENDIF.
ENDMETHOD.