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Core Data Services (CDS)

Language Reference Documentation

CDS is the backbone of the SAP Cloud Application Programming Model (CAP). It provides the means to declaratively capture service definitions and data models, queries, and expressions in plain (JavaScript) object notations. CDS features to parse from a variety of source languages and to compile them into various target languages.

CDS models are plain JavaScript objects complying to the Core Schema Notation (CSN), an open specification derived from JSON Schema. You can easily create or interpret these models, which foster extensions by 3rd-party contributions. Models are processed dynamically at runtime and can also be created dynamically.

See the Nature of Models for more details

Definition Language (CDL)
A reference and overview of all CDS concepts and features with compact examples written in CDS' definition language.
Schema Notation (CSN)
Specification of CSN, CDS' canonical format for representing CDS models as plain JavaScript objects, similar to JSON Schema.
Query Language (CQL)
Documents the CDS Query Language (aka CQL) which is an extension of the standard SQL SELECT statement.
Query Notation (CQN)
Specification of the Core Query Notation (CQN) format that is used to capture queries as plain JavaScript objects.
Expressions (CXN)
Specification of the Core Expression Notation (CXN) used to capture expressions as plain JavaScript objects.
Built-in Types
Find here a brief overview of the predefined types shipped with CDS.
Common Types and Aspects
Introduces @sap/cds/common, a prebuilt CDS model shipped with @sap/cds that provides common types and aspects.
Common Annotations
Find here a reference and glossary of common annotations intrinsically supported by the CDS compiler and runtimes.
Upgrade to Compiler v2
CDS compiler version 2 (cv2) brings numerous improvements, which allow us to significantly streamline model processing going forward. All projects are recommended to upgrade as soon as possible, as the former version will only receive critical fixes after cv2 is released.
Nature of Models
Introduces the fundamental principles of CDS models.