Simplified Extension Example

.gitignore

@@ -1,31 +0,0 @@
-# CAP multitenancy
-_out
-*.db
-connection.properties
-default-*.json
-gen/
-node_modules/
-target/
-
-# Web IDE, App Studio
-.che/
-.gen/
-
-# MTA
-*_mta_build_tmp
-*.mtar
-mta_archives/
-*mta-op*/
-
-# Other
-.DS_Store
-*.orig
-*.log
-
-*.iml
-*.flattened-pom.xml
-*log*.txt
-
-# IDEs
-# .vscode
-# .idea

db/assoc_extension.cds_

@@ -1,61 +1,44 @@
-using {sap.capire.bookshop} from '_base/db/schema';
-using {sap.capire.orders}   from '_base/db/schema';
-using from '_base/db/capire_common';
-
-using {
-    cuid, managed, Country, sap.common.CodeList
-} from '@sap/cds/common';
-
-namespace Z_bookshop.extension;
-
-// extend existing entity 
-extend orders.Orders with { 
-  Z_Customer    : Association to one Z_Customers;  
-  Z_SalesRegion : Association to one Z_SalesRegion; 
-  Z_priority    : String @assert.range enum {high; medium; low} default 'medium';
-  Z_Remarks     : Composition of many Z_Remarks on Z_Remarks.parent = $self;
-}  
-
-// new entity - as association target
-entity Z_Customers : cuid, managed 
-{
-  email        : String;
-  firstName    : String;
-  lastName     : String; 
-  creditCardNo : String;
-  dateOfBirth  : Date;
-  status       : String   @assert.range enum {platinum; gold; silver; bronze} default 'bronze';
-  creditScore  : Decimal  @assert.range: [ 1.0, 100.0 ] default 50.0;
-  PostalAddresses : Composition of many Z_CustomerPostalAddresses on PostalAddresses.Customer = $self;
-}
-
-// new unique constraint (secondary index)
-annotate Z_Customers with @assert.unique: { email: [ email ] }   
-{
-  email @mandatory;    // mandatory check
-}
-
-// new entity - as composition target
-entity Z_CustomerPostalAddresses : cuid, managed 
-{
-  Customer       : Association to one Z_Customers;
-  description    : String;
-  street         : String;
-  town           : String;
-  country        : Country;
-}
-
-// new entity - as code list
-entity Z_SalesRegion: CodeList {
-  key regionCode : String(11);
-}
-
-// new entity - as composition target
-entity Z_Remarks : cuid, managed
-{  
-  parent      : Association to one orders.Orders;  
-  number      : Integer;  
-  remarksLine : String; 
-}
-
-
+using {sap.capire.bookshop} from '_base/db/schema';
+using {sap.capire.orders}   from '_base/db/schema';
+using from '_base/db/capire_common';
+//using {Z_bookshop.fieldExtension as field} from './field_extension';
+
+using {
+    cuid, managed, Country, sap.common.CodeList
+} from '@sap/cds/common';
+
+
+
+namespace Z_bookshop.assocExtension;
+
+
+// extend existing entity 
+extend orders.Orders with { 
+  Z_Customer    : Association to one Z_Customers;  
+  Z_SalesRegion : Association to one Z_SalesRegion; 
+}
+
+// new entity - as association target
+entity Z_Customers : cuid, managed 
+{
+  email        : String;
+  firstName    : String;
+  lastName     : String; 
+  creditCardNo : String;
+  dateOfBirth  : Date;
+  status       : String   @assert.range enum {platinum; gold; silver; bronze} default 'bronze';
+  creditScore  : Decimal  @assert.range: [ 1.0, 100.0 ] default 50.0;
+  
+}
+
+// new unique constraint (secondary index)
+annotate Z_Customers with @assert.unique: { email: [ email ] }   
+{
+  email @mandatory;    // mandatory check
+}
+
+
+// new entity - as code list
+entity Z_SalesRegion: CodeList {
+  key regionCode : String(11);
+}

db/comp_extension.cds_

@@ -0,0 +1,41 @@
+using {sap.capire.bookshop} from '_base/db/schema';
+using {sap.capire.orders}   from '_base/db/schema';
+using from '_base/db/capire_common';
+using {Z_bookshop.assocExtension as assoc} from './assoc_extension';
+
+using {
+    cuid, managed, Country, sap.common.CodeList
+} from '@sap/cds/common';
+
+
+
+namespace Z_bookshop.compExtension;
+
+
+// extend existing entity 
+extend orders.Orders with { 
+  Z_Remarks     : Composition of many Z_Remarks on Z_Remarks.parent = $self;
+}  
+
+// new entity - as composition target
+entity Z_CustomerPostalAddresses : cuid, managed 
+{
+  Customer       : Association to one assoc.Z_Customers;
+  description    : String;
+  street         : String;
+  town           : String;
+  country        : Country;
+}
+
+
+// new entity - as composition target
+entity Z_Remarks : cuid, managed
+{  
+  parent      : Association to one orders.Orders;  
+  number      : Integer;  
+  remarksLine : String; 
+}
+
+extend assoc.Z_Customers with {
+  PostalAddresses : Composition of many Z_CustomerPostalAddresses on PostalAddresses.Customer = $self;
+}

db/data/Z_bookshop.extension-Z_CustomerPostalAddresses.csv_

@@ -1,5 +1,5 @@
-ID;modifiedAt;createdAt;createdBy;modifiedBy;Customer_ID;description;street;town;country_code
-1e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-04-04;2019-01-31;admin@business.com;admin@business.com;8e2f2640-6866-4dcf-8f4d-3027aa831cad;Home;Hauptstrasse 11;Berlin;DE
-24e718c9-ff99-47f1-8ca3-950c850777d4;2019-04-04;2019-01-30;admin@business.com;admin@business.com;74e718c9-ff99-47f1-8ca3-950c850777d4;Home;Main Street 22;London;GB
-3e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-04-04;2019-01-31;admin@business.com;admin@business.com;8e2f2640-6866-4dcf-8f4d-3027aa831cad;Work;Siemensstrasse 21;Berlin;DE
-44e718c9-ff99-47f1-8ca3-950c850777d4;2019-04-04;2019-01-30;admin@business.com;admin@business.com;74e718c9-ff99-47f1-8ca3-950c850777d4;Work;Work Street 34;London;GB
+ID;modifiedAt;createdAt;createdBy;modifiedBy;Customer_ID;description;street;town;country_code
+1e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-04-04;2019-01-31;admin@business.com;admin@business.com;8e2f2640-6866-4dcf-8f4d-3027aa831cad;Home;Hauptstrasse 11;Berlin;DE
+24e718c9-ff99-47f1-8ca3-950c850777d4;2019-04-04;2019-01-30;admin@business.com;admin@business.com;74e718c9-ff99-47f1-8ca3-950c850777d4;Home;Main Street 22;London;GB
+3e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-04-04;2019-01-31;admin@business.com;admin@business.com;8e2f2640-6866-4dcf-8f4d-3027aa831cad;Work;Siemensstrasse 21;Berlin;DE
+44e718c9-ff99-47f1-8ca3-950c850777d4;2019-04-04;2019-01-30;admin@business.com;admin@business.com;74e718c9-ff99-47f1-8ca3-950c850777d4;Work;Work Street 34;London;GB

db/data/Z_bookshop.extension-Z_Customers.csv_

@@ -1,3 +1,3 @@
-ID;modifiedAt;createdAt;createdBy;modifiedBy;email;firstName;lastName;creditCardNo;dateOfBirth;status;creditScore
-8e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-04-04;2019-01-31;admin@business.com;admin@business.com;john.doe@test.com;John;Doe;9977-6655-4433-2211;1970-01-01;gold;80.0
+ID;modifiedAt;createdAt;createdBy;modifiedBy;email;firstName;lastName;creditCardNo;dateOfBirth;status;creditScore
+8e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-04-04;2019-01-31;admin@business.com;admin@business.com;john.doe@test.com;John;Doe;9977-6655-4433-2211;1970-01-01;gold;80.0
 74e718c9-ff99-47f1-8ca3-950c850777d4;2019-04-04;2019-01-30;admin@business.com;admin@business.com;jane.doe@sap.com;Jane;Doe;2211-3344-5566-7788;1980-11-11;platinum;100.0

db/data/Z_bookshop.extension-Z_SalesRegion.csv_

@@ -1,4 +1,4 @@
-regionCode;name;descr
-AMER;Americas;North, Central and South America
-EMEA;Europe, the Middle East and Africa;Europe, the Middle East and Africa
+regionCode;name;descr
+AMER;Americas;North, Central and South America
+EMEA;Europe, the Middle East and Africa;Europe, the Middle East and Africa
 APJ;Asia Pacific and Japan;Asia Pacific and Japan

db/data/sap.capire.orders-Orders.csv

@@ -1,3 +1,3 @@
-ID;createdAt;createdBy;buyer;OrderNo;currency_code;Z_Customer_ID;Z_priority;Z_SalesRegion_regionCode
-7e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-01-31;john.doe@test.com;john.doe@test.com;1;EUR;8e2f2640-6866-4dcf-8f4d-3027aa831cad;high;EMEA
-64e718c9-ff99-47f1-8ca3-950c850777d4;2019-01-30;jane.doe@test.com;jane.doe@test.com;2;EUR;74e718c9-ff99-47f1-8ca3-950c850777d4;low;APJ
+ID;createdAt;createdBy;buyer;OrderNo;currency_code;Z_orderInfo;Z_internalNo;Z_expectedDelivery;Z_priority;Z_discount;
+7e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-01-31;john.doe@test.com;john.doe@test.com;1;EUR;Webshop order;202001;2019-03-31;high;5.0
+64e718c9-ff99-47f1-8ca3-950c850777d4;2019-01-30;jane.doe@test.com;jane.doe@test.com;2;EUR;Walk in order;202002;2019-04-15;low;10.0

db/data/sap.capire.orders-Orders.csv_

@@ -0,0 +1,3 @@
+ID;createdAt;createdBy;buyer;OrderNo;currency_code;Z_Customer_ID;Z_priority;Z_SalesRegion_regionCode
+7e2f2640-6866-4dcf-8f4d-3027aa831cad;2019-01-31;john.doe@test.com;john.doe@test.com;1;EUR;8e2f2640-6866-4dcf-8f4d-3027aa831cad;high;EMEA
+64e718c9-ff99-47f1-8ca3-950c850777d4;2019-01-30;jane.doe@test.com;jane.doe@test.com;2;EUR;74e718c9-ff99-47f1-8ca3-950c850777d4;low;APJ

db/field_extension.cds

@@ -0,0 +1,38 @@
+using {sap.capire.bookshop} from '_base/db/schema';
+using {sap.capire.orders} from '_base/db/schema';
+using from '_base/db/capire_common';
+
+using {
+  cuid,
+  managed,
+  Country,
+  sap.common.CodeList
+} from '@sap/cds/common';
+
+
+namespace Z_bookshop.fieldExtension;
+
+
+// extend existing entity
+extend orders.Orders with {
+  Z_orderInfo        : String default 'Webshop order';
+  Z_internalNo       : Integer; // uniqiue constraint
+  Z_expectedDelivery : Date; //mandatory
+  Z_priority         : String
+      @assert.range enum {
+      high;
+      medium;
+      low
+    } default 'medium';
+    Z_discount       : Decimal
+      @assert.range : [
+        0.0,
+        99.9
+      ] default 0.0;
+    }
+
+
+// new unique constraint (secondary index)
+annotate orders.Orders with @assert.unique : {Z_internalNo : [Z_internalNo]} {
+  Z_expectedDelivery @mandatory; // mandatory check
+}

gen/srv/.cfignore

@@ -0,0 +1 @@
+node_modules/

gen/srv/manifest.yml

@@ -0,0 +1,8 @@
+---
+applications:
+  - name: multitenancy-srv
+    path: .
+    memory: 256M
+    buildpacks:
+      - nodejs_buildpack
+    services:

gen/srv/package.json

@@ -0,0 +1,6 @@
+{
+    "name": "multitenancy",
+    "version": "0.1.0",
+    "description": "cds extension project",
+    "dependencies": {}
+}

node_modules/_base/app/admin/fiori-service.cds

@@ -0,0 +1,93 @@
+using { AdminService } from '../../db/schema';
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Books Object Page
+//
+
+annotate AdminService.Books with @(
+	UI: {
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>General}', Target: '@UI.FieldGroup#General'},
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Translations}', Target:  'texts/@UI.LineItem'},
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Details}', Target: '@UI.FieldGroup#Details'},
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Admin}', Target: '@UI.FieldGroup#Admin'},
+		],
+		FieldGroup#General: {
+			Data: [
+				{Value: title},
+				{Value: author_ID},
+				{Value: genre_ID},
+				{Value: descr},
+			]
+		},
+		FieldGroup#Details: {
+			Data: [
+				{Value: stock},
+				{Value: price},
+				{Value: currency_code, Label: '{i18n>Currency}'},
+			]
+		},
+		FieldGroup#Admin: {
+			Data: [
+				{Value: createdBy},
+				{Value: createdAt},
+				{Value: modifiedBy},
+				{Value: modifiedAt}
+			]
+		}
+	}
+);
+
+annotate AdminService.Authors with @(
+	UI: {
+		HeaderInfo: {
+			Description: {Value: lifetime}
+		},
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Details}', Target: '@UI.FieldGroup#Details'},
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Books}', Target: 'books/@UI.LineItem'},
+		],
+		FieldGroup#Details: {
+			Data: [
+				{Value: placeOfBirth},
+				{Value: placeOfDeath},
+				{Value: dateOfBirth},
+				{Value: dateOfDeath},
+				{Value: age, Label: '{i18n>Age}'},
+			]
+		},
+	}
+);
+
+
+
+////////////////////////////////////////////////////////////
+//
+//  Draft for Localized Data
+//
+
+annotate sap.capire.bookshop.Books with @fiori.draft.enabled;
+annotate AdminService.Books with @odata.draft.enabled;
+
+annotate AdminService.Books_texts with @(
+	UI: {
+		Identification: [{Value:title}],
+		SelectionFields: [ locale, title ],
+		LineItem: [
+			{Value: locale, Label: 'Locale'},
+			{Value: title, Label: 'Title'},
+			{Value: descr, Label: 'Description'},
+		]
+	}
+);
+
+// Add Value Help for Locales
+annotate AdminService.Books_texts {
+	locale @ValueList:{entity:'Languages',type:#fixed}
+}
+// In addition we need to expose Languages through AdminService
+using { sap } from '@sap/cds/common';
+extend service AdminService {
+	entity Languages as projection on sap.common.Languages;
+}

node_modules/_base/app/browse/fiori-service.cds

@@ -0,0 +1,50 @@
+using CatalogService from '../../srv/cat-service';
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Books Object Page
+//
+annotate CatalogService.Books with @(
+	UI: {
+  	HeaderInfo: {
+			TypeName: 'Book',
+			TypeNamePlural: 'Books',
+  		Description: {Value: author}
+  	},
+		HeaderFacets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Description}', Target: '@UI.FieldGroup#Descr'},
+		],
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Details}', Target: '@UI.FieldGroup#Price'},
+		],
+		FieldGroup#Descr: {
+			Data: [
+				{Value: descr},
+			]
+		},
+		FieldGroup#Price: {
+			Data: [
+				{Value: price},
+				{Value: currency.symbol, Label: '{i18n>Currency}'},
+			]
+		},
+	}
+);
+
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Books Object Page
+//
+annotate CatalogService.Books with @(
+	UI: {
+	  SelectionFields: [ ID, price, currency_code ],
+		LineItem: [
+			{Value: title},
+			{Value: author, Label:'{i18n>Author}'},
+			{Value: genre.name},
+			{Value: price},
+			{Value: currency.symbol, Label:' '},
+		]
+	},
+);

node_modules/_base/app/common.cds

@@ -0,0 +1,257 @@
+/*
+	Common Annotations shared by all apps
+*/
+
+using { sap.capire.bookshop as my } from '../db/schema';
+using { sap.common } from '../db/capire_common';
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Books Lists
+//
+annotate my.Books with @(
+	Common.SemanticKey: [title],
+	UI: {
+		Identification: [{Value:title}],
+		SelectionFields: [ ID, author_ID, price, currency_code ],
+		LineItem: [
+			{Value: ID},
+			{Value: title},
+			{Value: author.name, Label:'{i18n>Author}'},
+			{Value: genre.name},
+			{Value: stock},
+			{Value: price},
+			{Value: currency.symbol, Label:' '},
+		]
+	}
+) {
+	author @ValueList.entity:'Authors';
+};
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Books Details
+//
+annotate my.Books with @(
+	UI: {
+		HeaderInfo: {
+			TypeName: '{i18n>Book}',
+			TypeNamePlural: '{i18n>Books}',
+			Title: {Value: title},
+			Description: {Value: author.name}
+		},
+	}
+);
+
+
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Books Elements
+//
+annotate my.Books with {
+	ID @title:'{i18n>ID}' @UI.HiddenFilter;
+	title @title:'{i18n>Title}';
+	genre  @title:'{i18n>Genre}'  @Common: { Text: genre.name,  TextArrangement: #TextOnly };
+	author @title:'{i18n>Author}' @Common: { Text: author.name, TextArrangement: #TextOnly };
+	price @title:'{i18n>Price}';
+	stock @title:'{i18n>Stock}';
+	descr @UI.MultiLineText;
+}
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Genres List
+//
+annotate my.Genres with @(
+	Common.SemanticKey: [name],
+	UI: {
+		SelectionFields: [ name ],
+		LineItem:[
+			{Value: name},
+			{Value: parent.name, Label: 'Main Genre'},
+		],
+	}
+);
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Genre Details
+//
+annotate my.Genres with @(
+	UI: {
+		Identification: [{Value:name}],
+		HeaderInfo: {
+			TypeName: '{i18n>Genre}',
+			TypeNamePlural: '{i18n>Genres}',
+			Title: {Value: name},
+			Description: {Value: ID}
+		},
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>SubGenres}', Target: 'children/@UI.LineItem'},
+		],
+	}
+);
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Genres Elements
+//
+annotate my.Genres with {
+	ID  @title: '{i18n>ID}';
+	name  @title: '{i18n>Genre}';
+}
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Authors List
+//
+annotate my.Authors with @(
+	Common.SemanticKey: [name],
+	UI: {
+		Identification: [{Value:name}],
+		SelectionFields: [ name ],
+		LineItem:[
+			{Value: ID},
+			{Value: name},
+			{Value: dateOfBirth},
+			{Value: dateOfDeath},
+			{Value: placeOfBirth},
+			{Value: placeOfDeath},
+		],
+	}
+);
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Author Details
+//
+annotate my.Authors with @(
+	UI: {
+		HeaderInfo: {
+			TypeName: '{i18n>Author}',
+			TypeNamePlural: '{i18n>Authors}',
+			Title: {Value: name},
+			Description: {Value: dateOfBirth}
+		},
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Target: 'books/@UI.LineItem'},
+		],
+	}
+);
+
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Authors Elements
+//
+annotate my.Authors with {
+	ID @title:'{i18n>ID}' @UI.HiddenFilter;
+	name @title:'{i18n>Name}';
+	dateOfBirth @title:'{i18n>DateOfBirth}';
+	dateOfDeath @title:'{i18n>DateOfDeath}';
+	placeOfBirth @title:'{i18n>PlaceOfBirth}';
+	placeOfDeath @title:'{i18n>PlaceOfDeath}';
+}
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Languages List
+//
+annotate common.Languages with @(
+	Common.SemanticKey: [code],
+	Identification: [{Value:code}],
+	UI: {
+		SelectionFields: [ name, descr ],
+		LineItem:[
+			{Value: code},
+			{Value: name},
+		],
+	}
+);
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Language Details
+//
+annotate common.Languages with @(
+	UI: {
+		HeaderInfo: {
+			TypeName: '{i18n>Language}',
+			TypeNamePlural: '{i18n>Languages}',
+			Title: {Value: name},
+			Description: {Value: descr}
+		},
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Details}', Target: '@UI.FieldGroup#Details'},
+		],
+		FieldGroup#Details: {
+			Data: [
+				{Value: code},
+				{Value: name},
+				{Value: descr}
+			]
+		},
+	}
+);
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Currencies List
+//
+annotate common.Currencies with @(
+	Common.SemanticKey: [code],
+	Identification: [{Value:code}],
+	UI: {
+		SelectionFields: [ name, descr ],
+		LineItem:[
+			{Value: descr},
+			{Value: symbol},
+			{Value: code},
+		],
+	}
+);
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Currency Details
+//
+annotate common.Currencies with @(
+	UI: {
+		HeaderInfo: {
+			TypeName: '{i18n>Currency}',
+			TypeNamePlural: '{i18n>Currencies}',
+			Title: {Value: descr},
+			Description: {Value: code}
+		},
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Details}', Target: '@UI.FieldGroup#Details'},
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Extended}', Target: '@UI.FieldGroup#Extended'},
+		],
+		FieldGroup#Details: {
+			Data: [
+				{Value: name},
+				{Value: symbol},
+				{Value: code},
+				{Value: descr}
+			]
+		},
+		FieldGroup#Extended: {
+			Data: [
+				{Value: numcode},
+				{Value: minor},
+				{Value: exponent}
+			]
+		},
+	}
+);
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Currencies Elements
+//
+annotate common.Currencies with {
+	numcode @title:'{i18n>NumCode}';
+	minor @title:'{i18n>MinorUnit}';
+	exponent @title:'{i18n>Exponent}';
+}

node_modules/_base/app/orders/fiori-service.cds

@@ -0,0 +1,92 @@
+
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Note: this is designed for the OrdersService being co-located with
+//	bookshop. It does not work if OrdersService is run as a separate
+// 	process, and is not intended to do so.
+//
+////////////////////////////////////////////////////////////////////////////
+
+
+
+using { OrdersService } from '../../srv/orders-service';
+
+
+@odata.draft.enabled
+annotate OrdersService.Orders with @(
+	UI: {
+		SelectionFields: [ createdAt, createdBy ],
+		LineItem: [
+			{Value: OrderNo, Label:'OrderNo'},
+			{Value: buyer, Label:'Customer'},
+			{Value: createdAt, Label:'Date'}
+		],
+		HeaderInfo: {
+			TypeName: 'Order', TypeNamePlural: 'Orders',
+			Title: {
+				Label: 'Order number ', //A label is possible but it is not considered on the ObjectPage yet
+				Value: OrderNo
+			},
+			Description: {Value: createdBy}
+		},
+		Identification: [ //Is the main field group
+			{Value: createdBy, Label:'Customer'},
+			{Value: createdAt, Label:'Date'},
+			{Value: OrderNo },
+		],
+		HeaderFacets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Created}', Target: '@UI.FieldGroup#Created'},
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Modified}', Target: '@UI.FieldGroup#Modified'},
+		],
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>Details}', Target: '@UI.FieldGroup#Details'},
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>OrderItems}', Target: 'Items/@UI.LineItem'},
+		],
+		FieldGroup#Details: {
+			Data: [
+				{Value: currency.code, Label:'Currency'}
+			]
+		},
+		FieldGroup#Created: {
+			Data: [
+				{Value: createdBy},
+				{Value: createdAt},
+			]
+		},
+		FieldGroup#Modified: {
+			Data: [
+				{Value: modifiedBy},
+				{Value: modifiedAt},
+			]
+		},
+	},
+) {
+	createdAt @UI.HiddenFilter:false;
+	createdBy @UI.HiddenFilter:false;
+};
+
+
+
+annotate OrdersService.Orders_Items with @(
+	UI: {
+		LineItem: [
+			{Value: product_ID, Label:'Product ID'},
+			{Value: title, Label:'Product Title'},
+			{Value: price, Label:'Unit Price'},
+			{Value: amount, Label:'Quantity'},
+		],
+		Identification: [ //Is the main field group
+			{Value: amount, Label:'Amount'},
+			{Value: title, Label:'Product'},
+			{Value: price, Label:'Unit Price'},
+		],
+		Facets: [
+			{$Type: 'UI.ReferenceFacet', Label: '{i18n>OrderItems}', Target: '@UI.Identification'},
+		],
+	},
+) {
+	amount @(
+		Common.FieldControl: #Mandatory
+	);
+};

node_modules/_base/app/services.cds

@@ -0,0 +1,11 @@
+/*
+  This model controls what gets served to Fiori frontends...
+*/
+
+using from './admin/fiori-service';
+using from './browse/fiori-service';
+using from './orders/fiori-service';
+using from './common';
+
+using from '../db/capire_common';
+

node_modules/_base/db/capire_common.cds

@@ -0,0 +1,46 @@
+using { sap } from '@sap/cds/common';
+
+
+extend sap.common.Currencies with {
+  // Currencies.code = ISO 4217 alphabetic three-letter code
+  // with the first two letters being equal to ISO 3166 alphabetic country codes
+  // See also:
+  // [1] https://www.iso.org/iso-4217-currency-codes.html
+  // [2] https://www.currency-iso.org/en/home/tables/table-a1.html
+  // [3] https://www.ibm.com/support/knowledgecenter/en/SSZLC2_7.0.0/com.ibm.commerce.payments.developer.doc/refs/rpylerl2mst97.htm
+  numcode  : Integer;
+  exponent : Integer; //> e.g. 2 --> 1 Dollar = 10^2 Cent
+  minor    : String; //> e.g. 'Cent'
+}
+
+
+/**
+ * The Code Lists below are designed as optional extensions to
+ * the base schema. Switch them on by adding an Association to
+ * one of the code list entities in your models or by:
+ * annotate sap.common.Countries with @cds.persistence.skip:false;
+ */
+
+context sap.common_countries {
+
+  extend sap.common.Countries {
+    regions   : Composition of many Regions on regions._parent = $self.code;
+  }
+
+  entity Regions : sap.common.CodeList {
+    key code : String(5); // ISO 3166-2 alpha5 codes, e.g. DE-BW
+    children  : Composition of many Regions on children._parent = $self.code;
+    cities    : Composition of many Cities on cities.region = $self;
+    _parent   : String(11);
+  }
+  entity Cities : sap.common.CodeList {
+    key code  : String(11);
+    region    : Association to Regions;
+    districts : Composition of many Districts on districts.city = $self;
+  }
+  entity Districts : sap.common.CodeList {
+    key code  : String(11);
+    city      : Association to Cities;
+  }
+
+}

node_modules/_base/db/schema.cds

@@ -0,0 +1,4 @@
+using   from './schema_bookshop';
+using   from './schema_orders';
+
+annotate cds.UUID with @(Core.Computed : true);

node_modules/_base/db/schema_bookshop.cds

@@ -0,0 +1,31 @@
+using { Currency, managed, sap } from '@sap/cds/common';
+namespace sap.capire.bookshop;
+
+entity Books : managed {
+  key ID : Integer;
+  title  : localized String(111);
+  descr  : localized String(1111);
+  author : Association to Authors;
+  genre  : Association to Genres;
+  stock  : Integer;
+  price  : Decimal;
+  currency : Currency;
+  image : LargeBinary @Core.MediaType : 'image/png';
+}
+
+entity Authors : managed {
+  key ID : Integer;
+  name   : String(111);
+  dateOfBirth  : Date;
+  dateOfDeath  : Date;
+  placeOfBirth : String;
+  placeOfDeath : String;
+  books  : Association to many Books on books.author = $self;
+}
+
+/** Hierarchically organized Code List for Genres */
+entity Genres : sap.common.CodeList {
+  key ID   : Integer;
+  parent   : Association to Genres;
+  children : Composition of many Genres on children.parent = $self;
+}

node_modules/_base/db/schema_orders.cds

@@ -0,0 +1,23 @@
+using { Currency, User, managed, cuid } from '@sap/cds/common';
+namespace sap.capire.orders;
+
+entity Orders : cuid, managed {
+  OrderNo  : String @title:'Order Number'; //> readable key
+  Items    : Composition of many Orders_Items on Items.up_ = $self;
+  buyer    : User;
+  currency : Currency;
+}
+
+entity Orders_Items {
+  key ID    : UUID;
+  up_       : Association to Orders;
+  product   : Association to Products @assert.integrity:false; // REVISIT: this is a temporary workaround for a glitch in cds-runtime
+  amount    : Integer;
+  title     : String; //> intentionally replicated as snapshot from product.title
+  price     : Double;
+}
+
+/** This is a stand-in for arbitrary ordered Products */
+entity Products @(cds.persistence.skip:'always') {
+  key ID : String;
+}

node_modules/_base/node_modules/@sap/cds/common.cds

@@ -0,0 +1,135 @@
+type Language : Association to sap.common.Languages;
+type Currency : Association to sap.common.Currencies;
+type Country : Association to sap.common.Countries;
+
+/**
+ * Entities to serve the reuse types with extensible code lists
+ * including built-in support for value lists in Fiori.
+ */
+context sap.common {
+  entity Languages : CodeList {
+    key code : String(14) @(title : '{i18n>LanguageCode}');
+    //> length=14 is to accommodate values like these:
+    // en_US_x_saptrc - (1Q) used as a technical SAP language code
+    // en_US_x_sappsd - (2Q) used as a technical SAP language code
+  }
+
+  entity Countries : CodeList {
+    key code : String(3) @(title : '{i18n>CountryCode}');
+  }
+
+  entity Currencies : CodeList {
+    key code   : String(3) @(title : '{i18n>CurrencyCode}');
+        symbol : String(5) @(title : '{i18n>CurrencySymbol}');
+  }
+
+  aspect CodeList @(
+    cds.autoexpose,
+    cds.persistence.skip : 'if-unused'
+  ) {
+    name  : localized String(255)  @title : '{i18n>Name}';
+    descr : localized String(1000) @title : '{i18n>Description}';
+  }
+}
+
+
+/*
+ * Aspect for entities with canonical universal IDs.
+ */
+aspect cuid {
+  key ID : UUID; //> automatically filled in
+}
+
+/*
+ * Aspect to capture changes by user and name.
+ */
+aspect managed {
+  createdAt  : Timestamp @cds.on.insert : $now;
+  createdBy  : User      @cds.on.insert : $user;
+  modifiedAt : Timestamp @cds.on.insert : $now  @cds.on.update : $now;
+  modifiedBy : User      @cds.on.insert : $user @cds.on.update : $user;
+}
+
+/*
+ * Aspects for entities with temporal data.
+ */
+aspect temporal {
+  validFrom : Timestamp @cds.valid.from;
+  validTo   : Timestamp @cds.valid.to;
+}
+
+
+/**
+ * Canonical user ID
+ */
+type User : String(255);
+
+
+//---------------------------------------------------------------------------
+// Annotations for Fiori UIs...
+
+annotate sap.common.CodeList with @UI.Identification : [{Value:name}];
+annotate sap.common.CodeList with @cds.odata.valuelist;
+
+annotate managed with {
+  createdAt  @UI.HiddenFilter;
+  createdBy  @UI.HiddenFilter;
+  modifiedAt @UI.HiddenFilter;
+  modifiedBy @UI.HiddenFilter;
+}
+
+annotate managed with {
+  createdAt  @Core.Immutable;
+  createdBy  @Core.Immutable;
+}
+
+annotate sap.common.Countries  with { code @Common.Text:name; }
+annotate sap.common.Currencies with { code @Common.Text:name; }
+annotate sap.common.Languages  with { code @Common.Text:name; }
+
+
+//---------------------------------------------------------------------------
+// Common Annotations...
+
+annotate Language with @(
+  title       : '{i18n>Language}',
+  description : '{i18n>LanguageCode.Description}'
+);
+
+annotate Currency with @(
+  title       : '{i18n>Currency}',
+  description : '{i18n>CurrencyCode.Description}'
+);
+
+annotate Country with @(
+  title       : '{i18n>Country}',
+  description : '{i18n>CountryCode.Description}'
+);
+
+annotate User with @(
+  title       : '{i18n>UserID}',
+  description : '{i18n>UserID.Description}'
+);
+
+annotate managed with {
+  createdAt  @title : '{i18n>CreatedAt}';
+  createdBy  @title : '{i18n>CreatedBy}';
+  modifiedAt @title : '{i18n>ChangedAt}';
+  modifiedBy @title : '{i18n>ChangedBy}';
+}
+
+
+//---------------------------------------------------------------------------
+// Temporary Workarounds...
+
+// REVISIT: change @odata.on... to @cds.on...
+// REVISIT: @cds.on... should automatically result in @readonly @Core.Computed
+
+annotate managed with {
+  modifiedAt @readonly  @odata.on.update : #now;
+  createdAt  @readonly  @odata.on.insert : #now;
+  createdBy  @readonly  @odata.on.insert : #user;
+  modifiedBy @readonly  @odata.on.update : #user;
+}
+
+//---------------------------------------------------------------------------

node_modules/_base/srv/admin-service.cds

@@ -0,0 +1,7 @@
+using { sap.capire.bookshop as my } from '../db/schema';
+
+//service AdminService @(requires:'admin') {
+service AdminService {
+  entity Books as projection on my.Books;
+  entity Authors as projection on my.Authors;
+}

node_modules/_base/srv/cat-service.cds

@@ -0,0 +1,16 @@
+using { sap.capire.bookshop as my } from '../db/schema';
+service CatalogService @(path:'/browse') {
+
+  /** For displaying lists of Books */
+  @readonly entity ListOfBooks as projection on Books
+  excluding { descr };
+
+  /** For display in details pages */
+  @readonly entity Books as projection on my.Books { *,
+    author.name as author
+  } excluding { createdBy, modifiedBy };
+
+  //@__requires: 'authenticated-user'
+  action submitOrder ( book: Books:ID, amount: Integer ) returns { stock: Integer };
+  event OrderedBook : { book: Books:ID; amount: Integer; buyer: String };
+}

node_modules/_base/srv/mashup.cds

@@ -0,0 +1,27 @@
+////////////////////////////////////////////////////////////////////////////
+//
+//    Mashing up imported models...
+//
+
+using { sap.capire.bookshop.Books } from '../db/schema';
+
+//
+//  Extend Books with access to Reviews and average ratings
+//
+
+/*
+using { ReviewsService.Reviews } from '@capire/reviews';
+extend Books with {
+  reviews : Composition of many Reviews on reviews.subject = $self.ID;
+  rating  : Decimal;
+}
+*/
+
+//
+//  Extend Orders with Books as Products
+//
+
+using { sap.capire.orders.Orders_Items } from '../db/schema';
+extend Orders_Items with {
+  book : Association to Books on product.ID = book.ID
+}

node_modules/_base/srv/orders-service.cds

@@ -0,0 +1,5 @@
+using { sap.capire.orders as my } from '../db/schema';
+
+service OrdersService {
+  entity Orders as projection on my.Orders;
+}

srv/extension_service.cds

@@ -2,10 +2,5 @@ using from '_base/srv/admin-service';
 using from '_base/srv/cat-service';
 using from '_base/srv/orders-service';
 
-using { Z_bookshop.extension as ext } from '../db/extension';
+using from '../db/field_extension';
 
-
-extend service OrdersService with {
-   entity Z_Customers   as projection on ext.Z_Customers;
-   entity Z_SalesRegion as projection on ext.Z_SalesRegion;
-}

srv/extension_service_compassoc.cds_

@@ -0,0 +1,14 @@
+using from '_base/srv/admin-service';
+using from '_base/srv/cat-service';
+using from '_base/srv/orders-service';
+
+using from '../db/field_extension';
+using { Z_bookshop.compExtension as comp } from '../db/comp_extension';
+using { Z_bookshop.assocExtension as assoc } from '../db/assoc_extension';
+
+
+extend service OrdersService with {
+   entity Z_Customers   as projection on assoc.Z_Customers;
+   entity Z_SalesRegion as projection on assoc.Z_SalesRegion;
+}
+

srv/extension_service_ui.cds

@@ -1,210 +0,0 @@
-using from '_base/app/services';
-using OrdersService from './extension_service';
-
-// new entity -- draft enabled
-annotate OrdersService.Z_Customers with @odata.draft.enabled;
-
-// new entity -- titles
-annotate OrdersService.Z_Customers with {
-    ID           @(     
-        UI.Hidden,
-        Common : {Text : email}
-    );
-    firstName    @title : 'First Name';
-    lastName     @title : 'Last Name';
-    email        @title : 'Email';
-    creditCardNo @title : 'Credit Card No';
-    dateOfBirth  @title : 'Date of Birth';
-	status       @title : 'Status';
-	creditScore  @title : 'Credit Score';
-}
-
-// new entity -- titles
-annotate OrdersService.Z_CustomerPostalAddresses with {
-    ID          @(       
-        UI.Hidden,
-        Common : {Text : description}
-    );
-    description @title : 'Description';
-    street      @title : 'Street';
-    town        @title : 'Town';
-    country     @title : 'Country';
-}
-
-// new entity -- titles
-annotate OrdersService.Z_SalesRegion with {
-	regionCode      @title: 'Region Code';
-}
-
-// new entity -- titles
-annotate OrdersService.Z_Remarks with {
-    number          @title: 'Remark Number';
-	remarksLine     @title: 'Remark';
-}
-
-
-// new entity in service -- UI
-annotate OrdersService.Z_Customers with @(UI : {
-    HeaderInfo       : {
-        TypeName       : 'Customer',
-        TypeNamePlural : 'Customers',
-        Title          : {
-            $Type : 'UI.DataField',
-            Value : email
-        }
-    },
-    LineItem         : [
-        {Value : firstName},
-        {Value : lastName},
-        {Value : email},
-		{Value : status},
-        {Value : creditScore}
-    ],
-    Facets           : [
-		{$Type: 'UI.ReferenceFacet', Label: 'Main', Target : '@UI.FieldGroup#Main'},
-		{$Type: 'UI.ReferenceFacet', Label: 'Customer Postal Addresses', Target: 'PostalAddresses/@UI.LineItem'}
-	],
-    FieldGroup #Main : {Data : [
-        {Value : firstName},
-        {Value : lastName},
-        {Value : email},
-		{Value : status},
-        {Value : creditScore}
-    ]}
-} ) ;
-
-// new entity -- UI
-annotate OrdersService.Z_CustomerPostalAddresses with @(UI : {
-    HeaderInfo       : {
-        TypeName       : 'CustomerPostalAddress',
-        TypeNamePlural : 'CustomerPostalAddresses',
-        Title          : {
-            $Type : 'UI.DataField',
-            Value : description
-        }
-    },
-    LineItem         : [
-        {Value : description},
-        {Value : street},
-        {Value : town},
-		{Value : country_code}
-	],
-    Facets           : [
-		{$Type: 'UI.ReferenceFacet', Label: 'Main', Target : '@UI.FieldGroup#Main'}
-	],
-    FieldGroup #Main : {Data : [
-        {Value : description},
-        {Value : street},
-        {Value : town},
-		{Value : country_code}
-    ]}
-}, ) {
-
-};
-
-// new entity -- UI
-annotate OrdersService.Z_SalesRegion with @(
-	UI: {
-		HeaderInfo: {
-			TypeName: 'Sales Region',
-			TypeNamePlural: 'Sales Regions',
-			Title          : {
-                $Type : 'UI.DataField',
-                Value : regionCode
-            }
-		},
-		LineItem: [
-			{Value: regionCode},   
-            {Value: name}, 
-            {Value: descr}   
-		],
-		Facets: [
-			{$Type: 'UI.ReferenceFacet', Label: 'Main',    Target: '@UI.FieldGroup#Main'}
-		],
-		FieldGroup#Main: {
-			Data: [
-		        {Value: regionCode},   
-				{Value: name}, 
-                {Value: descr}     
-			]
-		}
-	},
-) {
-
-};
-
-
-// new entity -- UI
-annotate OrdersService.Z_Remarks with @(
-	UI: {
-		HeaderInfo: {
-			TypeName: 'Remark',
-			TypeNamePlural: 'Remarks',
-			Title          : {
-                $Type : 'UI.DataField',
-				Value : number
-            }
-		},
-		LineItem: [
-			{Value: number},
-			{Value: remarksLine}       
-		],
-		Facets: [
-			{$Type: 'UI.ReferenceFacet', Label: 'Main',    Target: '@UI.FieldGroup#Main'}
-		],
-		FieldGroup#Main: {
-			Data: [
-		        {Value: number},
-			    {Value: remarksLine}       
-			]
-		}
-	},
-) {
-
-};
-
-// extend existing entity Orders with new extension fields and new composition
-
-annotate OrdersService.Orders with @(
-	UI: {
-		LineItem: [...,			
-			{Value: Z_Customer_ID,            Label:'Customer'},          // extension field
-			{Value: Z_SalesRegion_regionCode, Label:'Sales Region'},      // extension field
-			{Value: Z_priority,               Label:'Priority'},          // extension field		
-		],
-		Facets: [...,
-			{$Type: 'UI.ReferenceFacet', Label: 'Remarks', Target: 'Z_Remarks/@UI.LineItem'} // new composition		
-		],
-		FieldGroup#Details: {
-			Data: [...,         
-				{Value: Z_Customer_ID,            Label:'Customer'},      // extension field
-				{Value: Z_SalesRegion_regionCode, Label:'Sales Region'},  // extension field
-				{Value: Z_priority,               Label:'Priority'}       // extension field
-			]
-		}	
-	}
-);
-
-// new field in existing service -- exchange ID with text
- annotate OrdersService.Orders with {
-	Z_Customer @(
-		Common: {
-			//show email, not id for Customer in the context of Orders
-			Text: Z_Customer.email  , TextArrangement: #TextOnly,
-			ValueList: {
-				Label: 'Customers',
-				CollectionPath: 'Z_Customers',
-				Parameters: [
-					{ $Type: 'Common.ValueListParameterInOut',
-						LocalDataProperty: Z_Customer_ID,  
-						ValueListProperty: 'ID'            
-					},
-					{ $Type: 'Common.ValueListParameterDisplayOnly',
-						ValueListProperty: 'email'
-					}
-				]
-			}
-		} 
-	);
-} 
-

srv/extension_service_ui_assoc.cds_

@@ -0,0 +1,311 @@
+using from '_base/app/services';
+using OrdersService from './extension_service';
+
+
+// new entity -- draft enabled
+annotate OrdersService.Z_Customers with @odata.draft.enabled;
+// new codelist entity -- draft enabled
+annotate OrdersService.Z_SalesRegion with @odata.draft.enabled;
+
+
+// new entity -- titles
+annotate OrdersService.Z_Customers with {
+  ID           @(
+    UI.Hidden,
+    Common : {Text : email}
+  );
+  firstName    @title : 'First Name';
+  lastName     @title : 'Last Name';
+  email        @title : 'Email';
+  creditCardNo @title : 'Credit Card No';
+  dateOfBirth  @title : 'Date of Birth';
+  status       @title : 'Status';
+  creditScore  @title : 'Credit Score';
+}
+
+// new entity -- titles
+annotate OrdersService.Z_CustomerPostalAddresses with {
+  ID          @(
+    UI.Hidden,
+    Common : {Text : description}
+  );
+  description @title : 'Description';
+  street      @title : 'Street';
+  town        @title : 'Town';
+  country     @title : 'Country';
+}
+
+// new entity -- titles
+annotate OrdersService.Z_SalesRegion with {
+  regionCode @title : 'Region Code';
+}
+
+// new entity -- titles
+annotate OrdersService.Z_Remarks with {
+  number      @title : 'Remark Number';
+  remarksLine @title : 'Remark';
+}
+
+
+// new entity in service -- UI
+annotate OrdersService.Z_Customers with @(UI : {
+  HeaderInfo       : {
+    TypeName       : 'Customer',
+    TypeNamePlural : 'Customers',
+    Title          : {
+      $Type : 'UI.DataField',
+      Value : email
+    }
+  },
+  LineItem         : [
+    {Value : firstName},
+    {Value : lastName},
+    {Value : email},
+    {Value : status},
+    {Value : creditScore}
+  ],
+  Facets           : [
+    {
+      $Type  : 'UI.ReferenceFacet',
+      Label  : 'Main',
+      Target : '@UI.FieldGroup#Main'
+    },
+    {
+      $Type  : 'UI.ReferenceFacet',
+      Label  : 'Customer Postal Addresses',
+      Target : 'PostalAddresses/@UI.LineItem'
+    }
+  ],
+  FieldGroup #Main : {Data : [
+    {Value : firstName},
+    {Value : lastName},
+    {Value : email},
+    {Value : status},
+    {Value : creditScore}
+  ]}
+});
+
+// new entity -- UI
+annotate OrdersService.Z_CustomerPostalAddresses with @(UI : {
+  HeaderInfo       : {
+    TypeName       : 'CustomerPostalAddress',
+    TypeNamePlural : 'CustomerPostalAddresses',
+    Title          : {
+      $Type : 'UI.DataField',
+      Value : description
+    }
+  },
+  LineItem         : [
+    {Value : description},
+    {Value : street},
+    {Value : town},
+    {Value : country_code}
+  ],
+  Facets           : [{
+    $Type  : 'UI.ReferenceFacet',
+    Label  : 'Main',
+    Target : '@UI.FieldGroup#Main'
+  }],
+  FieldGroup #Main : {Data : [
+    {Value : description},
+    {Value : street},
+    {Value : town},
+    {Value : country_code}
+  ]}
+}, ) {
+
+};
+
+// new entity -- UI
+annotate OrdersService.Z_SalesRegion with @(UI : {
+  HeaderInfo       : {
+    TypeName       : 'Sales Region',
+    TypeNamePlural : 'Sales Regions',
+    Title          : {
+      $Type : 'UI.DataField',
+      Value : regionCode
+    }
+  },
+  LineItem         : [
+    {Value : regionCode},
+    {Value : name},
+    {Value : descr}
+  ],
+  Facets           : [{
+    $Type  : 'UI.ReferenceFacet',
+    Label  : 'Main',
+    Target : '@UI.FieldGroup#Main'
+  }],
+  FieldGroup #Main : {Data : [
+    {Value : regionCode},
+    {Value : name},
+    {Value : descr}
+  ]}
+}, ) {
+
+};
+
+
+// new entity -- UI
+annotate OrdersService.Z_Remarks with @(UI : {
+  HeaderInfo       : {
+    TypeName       : 'Remark',
+    TypeNamePlural : 'Remarks',
+    Title          : {
+      $Type : 'UI.DataField',
+      Value : number
+    }
+  },
+  LineItem         : [
+    {Value : number},
+    {Value : remarksLine}
+  ],
+  Facets           : [{
+    $Type  : 'UI.ReferenceFacet',
+    Label  : 'Main',
+    Target : '@UI.FieldGroup#Main'
+  }],
+  FieldGroup #Main : {Data : [
+    {Value : number},
+    {Value : remarksLine}
+  ]}
+}, ) {
+
+};
+
+// extend existing entity Orders with new extension fields and new composition
+
+@odata.draft.enabled
+annotate OrdersService.Orders with @(UI : {
+  SelectionFields      : [
+    createdAt,
+    createdBy
+  ],
+  LineItem             : [
+    {
+      Value : OrderNo,
+      Label : 'OrderNo'
+    },
+    {
+      Value : Z_Customer_ID,
+      Label : 'Customer'
+    }, // extension field
+    {
+      Value : Z_SalesRegion_regionCode,
+      Label : 'Sales Region'
+    }, // extension field
+    {
+      Value : Z_priority,
+      Label : 'Priority'
+    }, // extension field
+    {
+      Value : createdAt,
+      Label : 'Date'
+    }
+  ],
+  HeaderInfo           : {
+    TypeName       : 'Order',
+    TypeNamePlural : 'Orders',
+    Title          : {
+      Label : 'Order number ', //A label is possible but it is not considered on the ObjectPage yet
+      Value : OrderNo
+    },
+    Description    : {Value : createdBy}
+  },
+  Identification       : [ //Is the main field group
+    {
+      Value : createdBy,
+      Label : 'Customer'
+    },
+    {
+      Value : createdAt,
+      Label : 'Date'
+    },
+    {Value : OrderNo},
+  ],
+  HeaderFacets         : [
+    {
+      $Type  : 'UI.ReferenceFacet',
+      Label  : '{i18n>Created}',
+      Target : '@UI.FieldGroup#Created'
+    },
+    {
+      $Type  : 'UI.ReferenceFacet',
+      Label  : '{i18n>Modified}',
+      Target : '@UI.FieldGroup#Modified'
+    },
+  ],
+  Facets               : [
+    {
+      $Type  : 'UI.ReferenceFacet',
+      Label  : '{i18n>Details}',
+      Target : '@UI.FieldGroup#Details'
+    },
+    {
+      $Type  : 'UI.ReferenceFacet',
+      Label  : '{i18n>OrderItems}',
+      Target : 'Items/@UI.LineItem'
+    },
+    {
+      $Type  : 'UI.ReferenceFacet',
+      Label  : 'Remarks',
+      Target : 'Z_Remarks/@UI.LineItem'
+    } // new composition
+  ],
+  FieldGroup #Details  : {Data : [
+    {
+      Value : currency_code,
+      Label : 'Currency'
+    },
+    {
+      Value : Z_Customer_ID,
+      Label : 'Customer'
+    }, // extension field
+    {
+      Value : Z_SalesRegion_regionCode,
+      Label : 'Sales Region'
+    }, // extension field
+    {
+      Value : Z_priority,
+      Label : 'Priority'
+    } // extension field
+  ]},
+  FieldGroup #Created  : {Data : [
+    {Value : createdBy},
+    {Value : createdAt},
+  ]},
+  FieldGroup #Modified : {Data : [
+    {Value : modifiedBy},
+    {Value : modifiedAt},
+  ]},
+}, )
+
+{
+  createdAt @UI.HiddenFilter : false;
+  createdBy @UI.HiddenFilter : false;
+};
+
+
+// new field in existing service -- exchange ID with text
+annotate OrdersService.Orders with {
+  Z_Customer @(Common : {
+    //show email, not id for Customer in the context of Orders
+    Text            : Z_Customer.email,
+    TextArrangement : #TextOnly,
+    ValueList       : {
+      Label          : 'Customers',
+      CollectionPath : 'Z_Customers',
+      Parameters     : [
+        {
+          $Type             : 'Common.ValueListParameterInOut',
+          LocalDataProperty : Z_Customer_ID,
+          ValueListProperty : 'ID'
+        },
+        {
+          $Type             : 'Common.ValueListParameterDisplayOnly',
+          ValueListProperty : 'email'
+        }
+      ]
+    }
+  });
+}

srv/extension_service_ui_fields.cds

@@ -0,0 +1,70 @@
+using from '_base/app/services';
+using OrdersService from './extension_service';
+
+
+// extend existing entity Orders with new extension fields and new composition
+
+@odata.draft.enabled
+annotate OrdersService.Orders with @(UI : {
+  LineItem            : [
+    {
+      Value : OrderNo,
+      Label : 'OrderNo'
+    },
+    {
+      Value : Z_orderInfo,
+      Label : 'Additional Information'
+    }, // extension field
+    {
+      Value : Z_internalNo,
+      Label : 'Internal Order Number'
+    }, // extension field
+    {
+      Value : Z_expectedDelivery,
+      Label : 'Expecxted Delivery Date'
+    }, // extension field
+    {
+      Value : Z_priority,
+      Label : 'Priority'
+    }, // extension field
+    {
+      Value : Z_discount,
+      Label : 'Discount'
+    }, // extension field
+    {
+      Value : createdAt,
+      Label : 'Date'
+    },
+  ],
+  FieldGroup #Details : {Data : [
+    {
+      Value : currency_code,
+      Label : 'Currency'
+    },
+    {
+      Value : Z_orderInfo,
+      Label : 'Additional Information'
+    }, // extension field
+    {
+      Value : Z_internalNo,
+      Label : 'Internal Order Number'
+    }, // extension field
+    {
+      Value : Z_expectedDelivery,
+      Label : 'Expected Delivery Date'
+    }, // extension field
+    {
+      Value : Z_priority,
+      Label : 'Priority'
+    }, // extension field
+    {
+      Value : Z_discount,
+      Label : 'Discount'
+    }, // extension field
+  ]},
+})
+
+{
+  createdAt @UI.HiddenFilter : false;
+  createdBy @UI.HiddenFilter : false;
+};