3.2 ABAP CDS in ABAP Dictionary

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The ABAP Core Data Services (ABAP CDS) are the implementation of the general CDS concept for AS ABAP. ABAP CDS makes it possible to define semantic data models on the central database of the application server. On AS ABAP, these models can be defined independently of the database system. The entities of these models provide enhanced access functions when 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 data definition language (DDL) and data control language (DCL) provided by ABAP CDS in the ABAP CDS syntax in CDS source code. The CDS objects defined with these languages are integrated into ABAP Dictionary and managed here. Currently, the following CDS objects can be defined here:
  • CDS data definitions
CDS data definitions are made using the ABAP CDS DDL. 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).
    • CDS views 
CDS entities, which from a technical perspective are based on CDS database views of the ABAP Dictionary.
    • CDS table functions 
CDS entities, which are implemented in AMDP functions.

The ABAP CDS DDL also contains language elements that enhance CDS entities.
  • CDS access controls
CDS access controls are based on CDS roles that are defined in DCL. When CDS entities that are assigned a CDS role are accessed, additional access conditions are evaluated by default.

Notes: 
  • CDS objects are transported using the CDS source code. The CDS entities defined using a CDS data definition are created after the transport when activated in the target system.
  • CDS source code can only be programmed in the Eclipse-based ABAP Development Tools (ADT). The Data Definition Language (DDL) and the Data Control Language (DCL) use different editors. The ADT documentation describes how these editors are used.
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