ABAP - Keyword Documentation →  ABAP - Dictionary → 

ABAP CDS in ABAP Dictionary

The ABAP Core Data Services (ABAP CDS) are the platform-independent implementation of the general CDS concept for AS ABAP. The ABAP CDS make it possible to define semantic data models on the standard AS ABAP database. Unlike the SAP HANA-specific variant HANA CDS, the ABAP CDS are independent of the database system. The entities of the models defined in ABAP CDS provide enhanced access functions compared with existing database tables and views defined in ABAP Dictionary, making it possible to optimize Open SQL-based applications. This is particularly clear when an AS ABAP uses a SAP HANA database, since its in-memory characteristics can be implemented in an optimum manner.

The data models are defined in the form of CDS objects using the CDS DDL and CDS DCL provided by ABAP CDS in the syntax of ABAP CDS in CDS source code. The CDS objects defined with these languages are integrated into ABAP Dictionary and managed here. CDS annotations can be used to define metadata for CDS objects.

A CDS annotation adds metadata to a CDS object. Annotations can be specified in DDL source code and DCL source code and moved to metadata extensions. Annotation definitions can be used to created an annotation itself as a CDS object. An annotation definition dictates how an annotation is used.
CDS data definitions are created using the CDS DDL of the ABAP CDS in the DDL source code. They define the following CDS entities. These units can be accessed as a data type (in ABAP programs) and as a data source (in Open SQL read statements).
The CDS DDL of the ABAP CDS also contains language elements that enhance CDS entities.
CDS access controls are based on CDS roles that are defined in CDS DCL in DCL source code. When CDS entities that are assigned a CDS role are accessed, additional access conditions are evaluated by default.


ABAP CDS - Syntax
ABAP CDS - Annotations
ABAP CDS - Data Definitions
ABAP CDS - Access Control
ABAP CDS - Performance Note