.

orders/api/external.cds

@@ -0,0 +1,9 @@
+context external {
+
+  /** This is a stand-in for arbitrary ordered Products */
+  entity Products @(cds.persistence.skip:'always') {
+    key ID : String;
+    data : String;
+  }
+
+}

orders/api/orders-service-comp.cds

@@ -0,0 +1,21 @@
+using { cuid, managed, User, Currency } from '@sap/cds/common';
+using { sap.capire.orders as my } from '../db/schema';
+using { external.Products } from './external';
+
+
+service OrdersService {
+
+  entity Orders : cuid, managed {
+    OrderNo  : String @title:'Order Number'; //> readable key
+    Items    : Composition of many {
+      key ID    : UUID;
+      product   : Association to Products;
+      amount    : Integer;
+      title     : String; //> intentionally replicated as snapshot from product.title
+      price     : Double;
+    };
+    buyer    : User;
+    currency : Currency;
+  }
+
+}

orders/api/orders-service.cds

@@ -0,0 +1,40 @@
+using { cuid, managed, User, Currency } from '@sap/cds/common';
+using { sap.capire.orders as my } from '../db/schema';
+using { external.Products } from './external';
+
+
+// GET Orders
+// GET Orders()/Items
+// GET Orders?$Items
+
+service OwnService {
+  entity Orders as projection on OrdersService.Orders;
+  entity Products as projection on OrdersService.Products;
+}
+
+service OrdersService {
+
+  entity Orders : cuid, managed {
+    OrderNo  : String @title:'Order Number'; //> readable key
+    Items    : Composition of many Orders_Items; // on Items.up_ = $self;
+    // MoreItems    : Composition of many Orders_Items; // on Items.up_ = $self;
+     // Items_ID
+    buyer    : User;
+    currency : Currency;
+  }
+
+  entity Orders_Items {
+    key ID    : UUID;
+    // up_       : Association to Orders;
+    product   : Association to Products; //> {ID}
+    // product_ID
+    amount    : Integer;
+    title     : String; //> intentionally replicated as snapshot from product.title
+    price     : Double;
+  }
+
+  // entity Products {
+  //   key ID : UUID;
+  // }
+
+}