DDIC-basierte CDS Views and Entity-basierte CDS Views

Differences and areas of application.

CDS Views have fundamentally changed data modeling in SAP HANA and ABAP, because with Core Data Services, data models are defined on the database rather than on the application server. CDS views are converted as database views, so that all data accesses, calculations are performed at database level. There are two main types of CDS views, each with its own advantages and disadvantages, which means they can be used for different purposes.

How do DDIC-based CDS views and entity-based CDS views differ?

DDIC-based CDS Views

CDS views based on DDIC—the data dictionary in SAP—use existing tables from the database as well as classic ABAP dictionary views.

Advantages:

• Compatibility: Good backward compatibility with existing database objects.
• Data integrity: Inheritance of primary/foreign key relationships.
• Stability: Robust and proven data models.

Disadvantages:

• Less flexible: Limited modern modeling capabilities.
• Performance: may be slower with large amounts of data.
• Stability: Robust and proven data models.

Entity-based CDS Views

Entity-based CDS views are more flexible and are based on so-called “entities,” i.e., reusable data structures.

Advantages:

• Agility: Quick adaptation to new requirements.
• Advanced modeling: associations, navigation, annotations.
• Optimization: Improved performance by executing computationally intensive operations directly on the SAP HANA database (SAP HANA Pushdown).

Disadvantages:

• Complexity: Requires deeper knowledge of data modeling.
• Learning curve: Developers must become accustomed to new concepts

When should you use DDIC-based CDS views and when should you use entity-based CDS views?

DDIC-based CDS views should be used for projects with a lot of legacy code and/or when simple data models are sufficient. Another argument in favor of their use is the importance of backward compatibility.

Entity-based CDS views have a clear advantage when agile, complex data models are in use or SAP HANA optimization is crucial.