SAP CDS Views: Revolutionizing Data Modeling in SAP HANA

The landscape of data modeling in SAP systems has undergone a significant transformation with the advent of SAP HANA. At the core of this revolution lies the concept of Core Data Services (CDS) Views. If you are still relying solely on traditional ABAP dictionary views or classical procedures for complex data retrieval, it's time to understand why CDS Views are the modern standard and a mandatory tool for any SAP developer.

What are SAP CDS Views?

SAP Core Data Services (CDS) provide a powerful and semantic data modeling infrastructure within the SAP HANA ecosystem. Essentially, a CDS View is an advanced layer built on top of SQL, allowing developers to define and consume persistent data models directly in the database layer (HANA) rather than the application layer (ABAP). This shift is critical as it embodies the "Code-to-Data" paradigm, pushing processing closer to the data source.

Use Case: Why Go with CDS Views in SAP HANA?

The transition to CDS Views is mandatory for modern SAP development, driven by several key benefits:

1. Performance and Efficiency (In-Memory Computing)

By defining calculation and aggregation logic directly in the database, CDS views leverage HANA's in-memory capabilities to the maximum. Computation happens instantly on the database server, eliminating the need to transfer vast amounts of raw data to the application server for processing, resulting in dramatic performance improvements.

2. Semantic Modeling and Annotations

CDS Views are fundamentally rich in metadata. Through annotations (e.g., @OData.publish: true, @Analytics.query: true), developers can instantly turn a data model into a ready-to-use OData service for Fiori apps or an analytic source for reporting tools. This significantly cuts down on boilerplate coding.

3. Path Expressions and Associations

CDS replaces complex, verbose SQL joins with simple, reusable associations. This allows developers to navigate between related entities using "path expressions," simplifying code readability and maintenance while ensuring optimal execution at the database level.

Code Explanation: Defining a Simple CDS View

The following snippet demonstrates the syntax for defining a basic ABAP CDS view utilizing DDL (Data Definition Language). This view selects customer sales data and establishes an association to the sales item table.

@AbapCatalog.sqlViewName: 'Z_CUST_SALES_SQL'
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'Customer Sales Overview CDS'

define view Z_I_CustomerSales 
  as select from snwd_so
  association [0..*] to snwd_so_item as _Item 
  on $projection.so_id = _Item.parent_key
{
  key so_id as SalesOrderID,
  buyer_guid as CustomerID,
  currency_code as Currency,
  gross_amount as TotalGrossAmount,
  
  // Exposing the association for navigation
  _Item
}

        

Key Elements Explained:

• Annotations (@): Provide semantic meaning and instruct the compiler on how to handle the view (e.g., security, exposing it as a service).
• define view Z_I_CustomerSales (CDS Entity Name): The primary name used by ABAP developers when selecting data via Open SQL.
• association (Relationship Definition): Replaces traditional joins for better encapsulation. The _Item alias allows us to access item details using a path expression like Z_I_CustomerSales._Item.
• $projection (Self-Reference): Used within the association definition to reference fields projected by the current view.

Summary

Moving from traditional data dictionary views to SAP CDS Views is a fundamental step toward maximizing your SAP HANA investment. By shifting logic to the database layer, leveraging semantic annotations, and defining complex relationships cleanly, CDS Views ensure that your SAP applications are built for speed, scalability, and the future of Fiori and analytical development.