What does it do? The RAP behavior definition header of an abstract BDEF can define the attributes listed below. The implementation type is mandatory; strict$[(version)$] and with hierarchy are strongly recommended for the following reasons: strict mode ensures that no outdated syntax can be used. When leaving out with hierarchy, the abstract BDEF represents the same derived type as a single CDS abstract entity and does not offer any additional value.
implementation type: an abstract BDEF must start with the keyword abstract.
strict$[(version)$]: It is strongly recommended that BDEF strict mode is used.
with hierarchy: causes the construction of a new kind of BDEF derived type for the entities that are part of the BDEF: Beginning at the RAP BO root entity, such a type contains all entity fields, plus a component for every composition. For a composition with cardinality <= 1, this component is a structure; otherwise, the component is a table. The type of the component (or its line type) is defined recursively in the same way, down to leaf level in the CDS composition hierarchy. The behavior definition header is followed by an entity behavior definition.
Latest notes: The addition with hierarchy is a precondition for the following components of an abstract BDEF:
ABAP Alternative 1@1@>with control
ABAP Alternative 2@2@>deep mapping
ABAP Alternative 2@2@>scalar entity
association _Assoc with hierarchy NON_V5_HINTS ABAP_HINT_END
