The new statement EXTEND ABSTRACT ENTITY>> of the DDL of ABAP CDS makes it possible to add new elements to existing CDS abstract entities> by using CDS abstract entity extensions>.
ABAP_MODIFICATION_NN CDS Abstract Entity, To-Parent Association >
In CDS abstract entities> , it is now possible to define to-parent associations> without ON> condition. The ON> condition can be left out if the association target is also a CDS abstract entity.
A hierarchy definition DEFINE HIERARCHY>> can now use the new addition CACHE ON$|OFF$|FORCE> to specify the caching policy for a generated hierarchy.
ABAP_MODIFICATION_NN Using CDS-Managed DDIC Views is Obsolete >
For each ABAP_CDS_V1_VIEW >, a ABAP_CDS_MNG_VIEW > is created in ABAP Dictionary upon activation. Using this ABAP_CDS_MNG_VIEW >, for example for typing or for accessing the CDS entity in question, is obsolete> from now on. The reason is the release of a new type of CDS entity, the CDS view entity>, which will replace ABAP_CDS_V1_VIEWS > in the future. CDS view entities do not have a ABAP_CDS_MNG_VIEW > attached and in case of a migration from ABAP_CDS_V1_VIEW to ABAP_CDS_V2_VIEW , each usage of a ABAP_CDS_MNG_VIEW > leads to a syntax error.
In CDS view entities>, it is now possible to reuse expressions defined in the SELECT> list in other operand positions of the same CDS view entity by using the syntax $projection.reuse_exp>>.
UNION>> clauses are now supported in CDS view entities>. There are a few differences to UNION> clauses in CDS DDIC-based views>. The most important difference is that branches of union clauses can be nested within each other in CDS view entities.
ABAP_MODIFICATION_NN CDS View Entity, DISTINCT>>
The addition DISTINCT>> is now available for SELECT> statements in CDS view entities>.