OData V4 Annotations (XML, ABAP CDS, CAP CDS)

OData V4 annotations are metadata decorators — expressed in XML, ABAP CDS, or CAP CDS syntax — that developers use to describe and configure the behavior of OData service entities for consumption by SAP Fiori elements UIs. They drive UI rendering decisions such as displaying images in tables, showing progress indicators in header facets, rendering link fields, and controlling value help text and ID display. By attaching annotations to service metadata, developers can declaratively shape how data is presented and interacted with — including delete dialog text, determining actions, and hierarchical tree structures — without writing custom UI logic.