SAP HANA - Core Data Service

About

Core Data Service (CDS) leverages the following language:

  • Data Definition Language to define the artifacts that make up the data-persistence model.
  • a query language (QL),
  • and an expression language (EL)

Artifact

You can save the data-persistence object definition as a CDS artifact. CDS documents are design-time source files that contain DDL code.

SAP HANA studio recognizes the .hdbdd file extension required for CDS object definitions and calls the appropriate repository plug-in to parse the content defined in the CDS document. (CDS Text Editor, View and edit DDL source code in a CDS document )

Example

namespace p1941293394trial.gerardnico.data;
// The name of the repository package in which you created the new CDS document

// The @Schema annotation defines the name of the schema to use to store the artifacts
// If the schema you specify does not exist, you cannot activate the new CDS document.
@Schema: '_SYS_BIC'
// A CDS document can only contain one top-level context
context MyModel {

 // Add structured types, if required.
 type BusinessKey : String(10);
 type SString  : String(40);
 
 // Contexts enable to group together related artifacts.
 context MasterData {
   @Catalog.tableType : #COLUMN 
    Entity Addresses {
        key  AddressId: BusinessKey;
        City: SString;
        PostalCode: BusinessKey;
        //<[...]>      
    };

  @Catalog.tableType : #COLUMN 
    Entity BusinessPartner {
        key  PartnerId: BusinessKey;
        PartnerRole: String(3); 
        //<[...]>  
    };
 };
 
 context Sales {
 //<[...]>
 };
 
 context Purchases {
 //<[...]>
 };
 
};

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