rap-cds

name

rap-cds

description

CDS view entity development for SAP RAP on ABAP Cloud/BTP. Covers creating and modifying CDS root view entities, child view entities, projection views, and metadata extensions with proper annotations for Fiori UI, search help, value help, and OData. Use this skill whenever the user wants to create or modify CDS views, add annotations, build data models, define associations/compositions, create projection views, or add metadata extensions. Trigger on: 'CDS view', 'annotations', 'data model', 'view entity', 'projection', 'metadata extension', '@UI', '@Search', 'value help', 'composition', 'association'.

RAP CDS View Entity Development

This skill helps create and modify CDS view entities for RAP Business Objects on ABAP Cloud/BTP, with proper annotations for Fiori Elements UI rendering.

Tools Used

• GetSource (object_type: "DDLS") — read existing CDS views
• WriteSource (object_type: "DDLS") — create/update CDS views
• EditSource — surgical edits to existing CDS views
• Activate — activate CDS objects
• SyntaxCheck — validate before activation
• GetCDSDependencies — understand CDS dependency trees
• SearchObject — find existing CDS entities

CDS View Entity Types in RAP

RAP uses a layered CDS architecture:

1. Interface View Entities (R-layer)

The core data model, prefix _R_ or _I_. These define the business object structure.

define root view entity ZR_TRAVEL
  as select from ztravel
  composition [0..*] of ZR_BOOKING as _Booking
{ ... }

2. Projection View Entities (C-layer)

Service-specific projections, prefix _C_. These adapt the interface layer for specific consumers.

define root view entity ZC_TRAVEL
  provider contract transactional_query
  as projection on ZR_TRAVEL
{ ... }

3. CDS Metadata Extensions

Separate annotation files that decouple UI metadata from the core data model.

@Metadata.layer: #CONSUMER
annotate view ZC_TRAVEL with
{ ... }

Composition and Association Patterns

Root to Child (Composition)

// In root entity
composition [0..*] of ZR_BOOKING as _Booking

// In child entity
association to parent ZR_TRAVEL as _Travel
  on $projection.TravelUUID = _Travel.TravelUUID

Child to Grandchild

// In child entity
composition [0..*] of ZR_BOOKING_SUPPLEMENT as _BookingSupplement

// In grandchild entity
association to parent ZR_BOOKING as _Booking
  on $projection.BookingUUID = _Booking.BookingUUID

Cross-BO Associations

association [0..1] to I_Currency as _Currency
  on $projection.CurrencyCode = _Currency.Currency

Cardinality Options

• [0..1] — zero or one (optional to-one)
• [1..1] or [1] — exactly one (mandatory to-one)
• [0..*] or [*] — zero or many (to-many)
• [1..*] — one or many

Essential Annotations

Semantic Annotations (Interface Layer)

These annotations enable the RAP framework to handle admin fields automatically in managed BOs:

@Semantics.user.createdBy: true
created_by as CreatedBy,

@Semantics.systemDateTime.createdAt: true
created_at as CreatedAt,

@Semantics.user.localInstanceLastChangedBy: true
local_last_changed_by as LocalLastChangedBy,

@Semantics.systemDateTime.localInstanceLastChangedAt: true
local_last_changed_at as LocalLastChangedAt,

@Semantics.systemDateTime.lastChangedAt: true
last_changed_at as LastChangedAt,

Amount and Quantity

@Semantics.amount.currencyCode: 'CurrencyCode'
total_price as TotalPrice,

@Semantics.quantity.unitOfMeasure: 'QuantityUnit'
quantity as Quantity,

UI Annotations (Projection/Metadata Extension Layer)

Header info:

@UI.headerInfo: {
  typeName: 'Travel',
  typeNamePlural: 'Travels',
  title: { type: #STANDARD, value: 'TravelID' },
  description: { type: #STANDARD, value: 'Description' }
}

List report and object page field positioning:

@UI.lineItem: [{ position: 10 }]
@UI.identification: [{ position: 10 }]
@UI.selectionField: [{ position: 10 }]
TravelID,

@UI.lineItem: [{ position: 20, importance: #HIGH }]
@UI.identification: [{ position: 20 }]
AgencyID,

@UI.lineItem: [{ position: 30, criticality: 'OverallStatusCriticality' }]
OverallStatus,

Facets for object page layout:

@UI.facet: [
  { id: 'GeneralInfo',
    type: #COLLECTION,
    label: 'General Information',
    position: 10 },
  { id: 'TravelData',
    parentId: 'GeneralInfo',
    type: #FIELDGROUP_REFERENCE,
    targetQualifier: 'TravelData',
    position: 10 },
  { id: 'BookingTable',
    type: #LINEITEM_REFERENCE,
    label: 'Bookings',
    position: 20,
    targetElement: '_Booking' }
]

Field groups:

@UI.fieldGroup: [{ qualifier: 'TravelData', position: 10 }]
AgencyID,

@UI.fieldGroup: [{ qualifier: 'TravelData', position: 20 }]
CustomerID,

Search Annotations

@Search.searchable: true

// On specific fields:
@Search.defaultSearchElement: true
@Search.fuzzinessThreshold: 0.7
Description,

Value Help Annotations

@Consumption.valueHelpDefinition: [{
  entity: { name: 'I_Currency', element: 'Currency' }
}]
CurrencyCode,

@Consumption.valueHelpDefinition: [{
  entity: { name: '/DMO/I_Agency', element: 'AgencyID' },
  additionalBinding: [{ localElement: 'AgencyName', element: 'Name' }]
}]
AgencyID,

Projection View Pattern

@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'Travel - Projection'
@Search.searchable: true
@Metadata.allowExtensions: true

define root view entity ZC_TRAVEL
  provider contract transactional_query
  as projection on ZR_TRAVEL
{
  key TravelUUID,
      @Search.defaultSearchElement: true
      TravelID,

      @Search.defaultSearchElement: true
      @ObjectModel.text.element: ['AgencyName']
      @Consumption.valueHelpDefinition: [{ entity: { name: '/DMO/I_Agency', element: 'AgencyID' } }]
      AgencyID,
      _Agency.Name as AgencyName,

      @Consumption.valueHelpDefinition: [{ entity: { name: '/DMO/I_Customer', element: 'CustomerID' } }]
      CustomerID,

      BeginDate,
      EndDate,

      @Semantics.amount.currencyCode: 'CurrencyCode'
      TotalPrice,

      @Consumption.valueHelpDefinition: [{ entity: { name: 'I_Currency', element: 'Currency' } }]
      CurrencyCode,

      Description,
      OverallStatus,

      CreatedBy,
      CreatedAt,
      LocalLastChangedBy,
      LocalLastChangedAt,
      LastChangedAt,

      /* Associations */
      _Booking : redirected to composition child ZC_BOOKING,
      _Agency,
      _Currency
}

Key points for projections:

• Use provider contract transactional_query for RAP projections
• Use redirected to composition child for composition associations
• Use redirected to parent for parent associations in child projections
• Add @Metadata.allowExtensions: true to enable metadata extensions

Metadata Extension Pattern

@Metadata.layer: #CONSUMER
@UI.headerInfo: {
  typeName: 'Travel',
  typeNamePlural: 'Travels',
  title: { type: #STANDARD, value: 'TravelID' },
  description: { type: #STANDARD, value: 'Description' }
}

annotate view ZC_TRAVEL with
{
  @UI.facet: [
    { id: 'GeneralInfo', type: #COLLECTION, label: 'General Information', position: 10 },
    { id: 'TravelDetails', parentId: 'GeneralInfo', type: #FIELDGROUP_REFERENCE,
      targetQualifier: 'TravelDetails', position: 10 },
    { id: 'Dates', parentId: 'GeneralInfo', type: #FIELDGROUP_REFERENCE,
      targetQualifier: 'Dates', position: 20 },
    { id: 'Bookings', type: #LINEITEM_REFERENCE, label: 'Bookings',
      position: 20, targetElement: '_Booking' }
  ]

  @UI.lineItem: [{ position: 10 }]
  @UI.selectionField: [{ position: 10 }]
  @UI.identification: [{ position: 10 }]
  TravelID;

  @UI.lineItem: [{ position: 20, importance: #HIGH }]
  @UI.fieldGroup: [{ qualifier: 'TravelDetails', position: 10 }]
  AgencyID;

  @UI.lineItem: [{ position: 30, importance: #HIGH }]
  @UI.fieldGroup: [{ qualifier: 'TravelDetails', position: 20 }]
  CustomerID;

  @UI.fieldGroup: [{ qualifier: 'Dates', position: 10 }]
  BeginDate;

  @UI.fieldGroup: [{ qualifier: 'Dates', position: 20 }]
  EndDate;

  @UI.lineItem: [{ position: 40 }]
  TotalPrice;

  @UI.lineItem: [{ position: 50, criticality: 'StatusCriticality' }]
  @UI.selectionField: [{ position: 20 }]
  OverallStatus;

  @UI.hidden: true
  TravelUUID;

  @UI.hidden: true
  CreatedBy;

  @UI.hidden: true
  CreatedAt;

  @UI.hidden: true
  LocalLastChangedBy;

  @UI.hidden: true
  LocalLastChangedAt;

  @UI.hidden: true
  LastChangedAt;
}

Common Tasks

Adding a new field to an existing CDS view

1. GetSource to read the current CDS DDL
2. EditSource to add the field in the select list
3. Update the BDEF mapping if needed (EditSource on BDEF)
4. Activate the CDS view, then the BDEF

Adding an association

1. Add the association definition after as select from
2. Expose the association in the select list
3. For projections, use redirected to syntax

Checking CDS dependencies

Use GetCDSDependencies to understand what tables/views a CDS entity reads from.

Validation Checklist

Before activating a CDS view, verify:

• All field aliases use CamelCase (ABAP Cloud convention)
• Semantic annotations are on the correct fields
• Compositions use composition [cardinality] of ChildEntity
• Parent associations use association to parent ParentEntity
• Currency/quantity reference fields point to exposed fields
• @AccessControl.authorizationCheck is specified (use #NOT_REQUIRED as default)