Simplified Extension Example

db/assoc_extension.cds_

@@ -0,0 +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 {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);
+}