/sap-abap

CDS View Entities - Complete Reference

Source: https://github.com/SAP-samples/abap-cheat-sheets/blob/main/15_CDS_View_Entities.md

Basic Syntax

@AbapCatalog.sqlViewName: 'ZSQL_VIEW'
@AbapCatalog.compiler.compareFilter: true
@AbapCatalog.preserveKey: true
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'Demo CDS View'

define view entity ZDemo_CDS_View
  as select from zdemo_table as Source
{
  key Source.key_field as KeyField,
      Source.field1    as Field1,
      Source.field2    as Field2
}

Field Selection

define view entity ZDemo_Fields
  as select from zdemo_table
{
  key key_field,                    // Direct field
      field1 as AliasName,          // With alias
      'Literal' as LiteralField,    // Literal value
      123 as NumericLiteral,        // Numeric literal
      abap.dats'20240101' as DateLiteral,  // Date literal
      $session.user as CurrentUser, // Session variable
      $session.client as Client
}

Expressions

Cast Expressions

cast( amount as abap.dec(15,2) ) as CastedAmount,
cast( quantity as abap.int4 ) as CastedQuantity,
cast( text as abap.char(100) ) as CastedText

Arithmetic Expressions

price * quantity as TotalAmount,
amount / 100 as AmountPercentage,
value1 + value2 as Sum,
value1 - value2 as Difference

Case Expressions

// Simple CASE
case status
  when 'A' then 'Active'
  when 'I' then 'Inactive'
  else 'Unknown'
end as StatusText,

// Searched CASE
case
  when amount > 1000 then 'High'
  when amount > 100 then 'Medium'
  else 'Low'
end as AmountCategory

Coalesce

coalesce( nullable_field, 'Default' ) as FieldWithDefault,
coalesce( amount, 0 ) as AmountOrZero

Built-in Functions

String Functions

concat( first_name, last_name ) as FullName,
concat_with_space( first_name, last_name, 1 ) as SpacedName,
substring( text, 1, 10 ) as Excerpt,
length( description ) as DescLength,
left( code, 2 ) as Prefix,
right( code, 2 ) as Suffix,
upper( name ) as UpperName,
lower( name ) as LowerName,
ltrim( text, ' ' ) as LeftTrimmed,
rtrim( text, ' ' ) as RightTrimmed,
replace( text, 'old', 'new' ) as ReplacedText,
instr( text, 'pattern' ) as PatternPosition

Numeric Functions

abs( amount ) as AbsoluteAmount,
ceil( value ) as Ceiling,
floor( value ) as FloorValue,
round( price, 2 ) as RoundedPrice,
div( total, count ) as IntegerDivision,
mod( number, 10 ) as Remainder,
division( amount, 3, 2 ) as PreciseDivision

Date/Time Functions

dats_is_valid( date_field ) as IsValidDate,
dats_days_between( date1, date2 ) as DaysDiff,
dats_add_days( date_field, 7 ) as DatePlusWeek,
dats_add_months( date_field, 1 ) as DatePlusMonth,
$session.system_date as Today

Type Conversion

cast( char_field as abap.numc(10) ) as NumericString,
cast( amount as abap.fltp ) as FloatingPoint

Aggregate Functions

define view entity ZDemo_Aggregates
  as select from zdemo_table
{
  key category,
  count(*) as TotalCount,
  count( distinct status ) as UniqueStatuses,
  sum( amount ) as TotalAmount,
  avg( price ) as AveragePrice,
  min( date_field ) as FirstDate,
  max( date_field ) as LastDate
}
group by category

Joins

Inner Join

define view entity ZDemo_InnerJoin
  as select from zdemo_header as Header
    inner join zdemo_item as Item
      on Header.header_id = Item.header_id
{
  key Header.header_id,
  key Item.item_id,
      Header.description,
      Item.quantity
}

Left Outer Join

define view entity ZDemo_LeftJoin
  as select from zdemo_header as Header
    left outer join zdemo_item as Item
      on Header.header_id = Item.header_id
{
  key Header.header_id,
      Header.description,
      Item.item_id,
      Item.quantity
}

Multiple Joins

define view entity ZDemo_MultiJoin
  as select from zdemo_header as Header
    inner join zdemo_item as Item
      on Header.header_id = Item.header_id
    left outer join zdemo_text as Text
      on Item.item_id = Text.item_id
{
  // fields
}

Associations

Definition

define view entity ZDemo_Associations
  as select from zdemo_header as Header
  association [1..*] to zdemo_item as _Items
    on Header.header_id = _Items.header_id
  association [0..1] to zdemo_status as _Status
    on Header.status = _Status.status_code
{
  key Header.header_id,
      Header.description,
      Header.status,

      // Expose associations
      _Items,
      _Status
}

Cardinalities

association [0..1] to Target    // Optional, single
association [1] to Target       // Mandatory, single
association [1..*] to Target    // One or more
association [0..*] to Target    // Zero or more (default)
association [*] to Target       // Same as [0..*]

Path Expressions

// Access associated fields
_Status.description as StatusDescription,
_Items.quantity as ItemQuantity

Annotations

CDS Annotations

@AbapCatalog.sqlViewName: 'ZSQLVIEW'
@AbapCatalog.preserveKey: true
@AbapCatalog.compiler.compareFilter: true

@AccessControl.authorizationCheck: #NOT_REQUIRED
// or #CHECK, #PRIVILEGED_ONLY

@EndUserText.label: 'Human readable name'

Element Annotations

define view entity ZDemo_Annotations
  as select from zdemo_table
{
  @EndUserText.label: 'Customer ID'
  @EndUserText.quickInfo: 'Unique customer identifier'
  key customer_id as CustomerId,

  @Semantics.amount.currencyCode: 'CurrencyCode'
  amount as Amount,

  @Semantics.currencyCode: true
  currency as CurrencyCode,

  @Semantics.unitOfMeasure: true
  unit as Unit,

  @Semantics.quantity.unitOfMeasure: 'Unit'
  quantity as Quantity
}

UI Annotations

@UI: {
  headerInfo: {
    typeName: 'Order',
    typeNamePlural: 'Orders',
    title: { value: 'OrderId' }
  }
}

@UI.lineItem: [{ position: 10 }]
@UI.identification: [{ position: 10 }]
key order_id as OrderId

Input Parameters

define view entity ZDemo_Parameters
  with parameters
    p_date : abap.dats,
    p_category : abap.char(10)
  as select from zdemo_table
{
  key id,
      description,
      $parameters.p_date as ParameterDate,
      $parameters.p_category as ParameterCategory
}
where category = $parameters.p_category
  and date_field >= $parameters.p_date

Calling with Parameters

SELECT * FROM zdemo_parameters( p_date = '20240101', p_category = 'A' )
  INTO TABLE @DATA(result).

Composition and Hierarchy

// Root entity
define root view entity ZDemo_Root
  as select from zdemo_root
  composition [0..*] of ZDemo_Child as _Children
{
  key root_id,
      description,
      _Children
}

// Child entity
define view entity ZDemo_Child
  as select from zdemo_child
  association to parent ZDemo_Root as _Root
    on $projection.root_id = _Root.root_id
{
  key root_id,
  key child_id,
      description,
      _Root
}

Extension Views

// Extend existing view
extend view entity ZExisting_View with
{
  Source.additional_field as AdditionalField,
  'Literal' as NewLiteral
}

ABAP Consumption

SELECT

" Direct select
SELECT * FROM zdemo_cds_view INTO TABLE @DATA(result).

" With association path
SELECT *, \_Items-quantity FROM zdemo_header
  INTO TABLE @DATA(with_items).

" With parameters
SELECT * FROM zdemo_params( p_date = @lv_date )
  INTO TABLE @DATA(parameterized).

Association Access

" Follow association
SELECT * FROM zdemo_header
  ASSOCIATION \_Items
  INTO TABLE @DATA(items).

Best Practices

1. Use view entities over classic CDS views
2. Define meaningful aliases for all fields
3. Expose associations for flexibility
4. Add semantic annotations for Fiori integration
5. Use parameters for flexible filtering
6. Document with @EndUserText annotations
7. Set appropriate authorization checks
8. Keep views focused and composable