namespace sap.capire.bookshop; using { sap.capire.bookshop } from '@capire/bookstore/srv/mashup'; entity GenreHierarchy : bookshop.Genres { hierarchyLevel : Integer default 0; drillState : String default 'leaf'; parent : Association to GenreHierarchy; children : Composition of many GenreHierarchy on children.parent = $self; } extend service CatalogService with { @readonly entity GenreHierarchy as projection on bookshop.GenreHierarchy; }