no replica context

suppliers/srv/mashup.cds

@@ -3,53 +3,23 @@
   you actually want to use from there.
  */
 
-using { API_BUSINESS_PARTNER as S4 } from './external/API_BUSINESS_PARTNER.csn';
-extend service S4 with {
-  entity Suppliers as projection on S4.A_BusinessPartner {
-    key BusinessPartner as ID,
-    BusinessPartnerFullName as name,
-    // REVISIT: following is not supported so far in cds compiler...
-    // to_BusinessPartnerAddress as city {
-    //    CityCode as code,
-    //    CityName as name
-    // }
-    // REVISIT: following is not supported so far in cqn2odata...
-    // to_BusinessPartnerAddress.CityCode as city,
-    // to_BusinessPartnerAddress.CityName as city_name,
-  }
+using {API_BUSINESS_PARTNER as S4} from './external/API_BUSINESS_PARTNER.csn';
+
+@cds.autoexpose // or expose explicitly in Catalog and AdminService
+@cds.persistence: {table,skip:false}
+entity sap.capire.bookshop.Suppliers as projection on S4.A_BusinessPartner {
+  key BusinessPartner as ID, BusinessPartnerFullName as name
 }
 
-
-/*
-  You can mashup entities from external services, or projections
-  thereof, with your project's own entities
- */
 using { sap.capire.bookshop.Books, CatalogService } from '@capire/bookshop';
 extend Books with {
-  supplier : Association to S4.Suppliers;
+  supplier: Association to sap.capire.bookshop.Suppliers;
 }
 
-
-/*
-  You can also expose external entities through your own services
-  For this to work, you need to delegate the respective calls
-  addressed to your services into calls to the external service.
- */
-extend service AdminService with {
-  entity Suppliers as projection on S4.Suppliers;
+extend service AdminService with { // why is AdminService visible?
+  entity Suppliers as projection on sap.capire.bookshop.Suppliers;
 }
 
-/*
-  Optionally add a local persistence to keep replicas of external
-  entities to have data in fast access locally; much like a cache.
- */
-annotate S4.Suppliers with @cds.persistence:{table,skip:false};
-
-/**
-  Having locally cached replicas also allows us to display supplier
-  data in lists of books, which otherwise would generate unwanted
-  traffic on S4 backends.
- */
 extend projection CatalogService.ListOfBooks with {
   supplier
 }