Sap Abap Cds

secondsky/sap-abap-cds

Comprehensive SAP ABAP CDS (Core Data Services) reference for data modeling, view development, and semantic enrichment. Use when creating CDS views or view entities, defining data models with annotations, working with associations and cardinality, implementing input parameters, using built-in functions, writing CASE expressions, implementing access control with DCL, handling CURR/QUAN data types, troubleshooting CDS errors, querying CDS views from ABAP, or displaying data with SALV IDA. Covers ABAP 7.4+ through ABAP Cloud.

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Install

one command, takes just this skill from the repository

npx skills add https://github.com/secondsky/sap-skills --skill sap-abap-cds

What comes with it

82 364 bytes besides the instruction

README.md

agents/openai.yaml

references/access-control-reference.md

references/annotations-reference.md

references/associations-reference.md

references/expressions-reference.md

references/functions-reference.md

references/troubleshooting.md

templates/basic-view.md

templates/dcl-template.md

templates/parameterized-view.md

The instruction itself

23 sections, as written by the author

SAP ABAP CDS (Core Data Services)

sap-abap: Use for ABAP programming patterns used with CDS or when implementing EML statements in ABAP
sap-btp-cloud-platform: Use for CDS deployment scenarios on BTP or ABAP Environment configurations
sap-fiori-tools: Use when building Fiori Elements applications that consume CDS views or working with UI annotations
sap-cap-capire: Use for comparing CDS syntax between ABAP and CAP or when integrating ABAP CDS with CAP services
sap-api-style: Use when documenting CDS-based OData services or following API documentation standards

When to Use This Skill

Use this skill when creating ABAP CDS views or view entities, defining associations and cardinalities, adding UI or semantic annotations, implementing DCL access control, handling currency/unit fields, troubleshooting CDS compiler errors, or comparing classic CDS views with newer view entities.

Quick Reference: https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/abencds.html | SAP Cheat Sheets: https://github.com/SAP-samples/abap-cheat-sheets/blob/main/15_CDS_View_Entities.md

Version Compatibility

This skill covers CDS features from 7.40 SP8 through ABAP Cloud. Key version boundaries:

| Feature | 7.40 SP8 | 7.50 | 7.51 | 7.55+ |

|---------|:--------:|:----:|:----:|:-----:|

| CDS View (DEFINE VIEW) | x | x | x | x |

| CDS associations, parameters, built-in functions | x | x | x | x |

| CDS Table Functions (DEFINE TABLE FUNCTION) | | x | x | x |

| CDS Access Control (DEFINE ROLE / pfcg_auth) | x | x | x | x |

| CDS Access Control (implicit evaluation) | | x | x | x |

| Session variables ($session.user/client/system_language) | x | x | x | x |

| @Environment.systemField annotation | | x | x | x |

| UPPER/LOWER functions | | | x | x |

| $session.system_date | | | x | x |

| CDS Metadata Extensions (ANNOTATE VIEW) | | | x | x |

| Cross Join in CDS | | | x | x |

| CDS View Entity (DEFINE VIEW ENTITY) | | | | x |

| New cardinality syntax (to one/to many) | | | | 7.57+ |

On a 7.40 system: Use DEFINE VIEW (not DEFINE VIEW ENTITY). CDS table functions

are not available before 7.50. Basic DCL (DEFINE ROLE with pfcg_auth) is available

from 7.40 SP08, but implicit role evaluation in ABAP SQL requires 7.50+.

$session.user/client/system_language are available from 7.40 SP08.

The templates in templates/ include both classic CDS View and View Entity variants.

1. CDS View Fundamentals
2. Essential Annotations
3. Expressions and Operations
4. Built-in Functions
5. Joins
6. Associations
7. Input Parameters
8. Aggregate Expressions
9. Access Control (DCL)
10. Data Retrieval from ABAP
11. Common Errors and Solutions
12. Useful Transactions and Tables
Bundled Resources
Source Documentation

1. CDS View Fundamentals

View Types

|------|--------|---------------|-------|

| CDS View | DEFINE VIEW | Yes | 7.4 SP8 |

| CDS View Entity | DEFINE VIEW ENTITY | No | 7.55 |

Recommendation: Use CDS View Entities for new development.

Basic CDS View Syntax

@AbapCatalog.sqlViewName: 'ZCDS_EXAMPLE_V'
@AbapCatalog.compiler.CompareFilter: true
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'Example CDS View'

define view ZCDS_EXAMPLE
  as select from db_table as t
{
  key t.field1,
      t.field2,
      t.field3 as AliasName
}

CDS View Entity Syntax (7.55+)

@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'Example View Entity'

define view entity Z_CDS_EXAMPLE
  as select from db_table as t
{
  key t.field1,
      t.field2,
      t.field3 as AliasName
}

Key Difference: View entities omit @AbapCatalog.sqlViewName - no SQL view generated.

Eclipse ADT Setup

File → New → Other → Core Data Services → Data Definition
Enter name, description, and package
Select template (view, view entity, etc.)

2. Essential Annotations

Core Annotations

Essential annotations for CDS development:

@AbapCatalog.sqlViewName - SQL view name (max 16 chars)
@AbapCatalog.compiler.CompareFilter - Optimize WHERE clauses
@AccessControl.authorizationCheck - Set to #NOT_REQUIRED, #CHECK, #MANDATORY, or #NOT_ALLOWED
@EndUserText.label - User-facing description
@Metadata.allowExtensions - Allow view extensions

Complete Reference: See references/annotations-reference.md for 50+ annotations with examples.

Semantics Annotations (Currency/Quantity)

Required for CURR and QUAN data types to avoid error SD_CDS_ENTITY105:

-- Currency fields
@Semantics.currencyCode: true
waers,
@Semantics.amount.currencyCode: 'waers'
amount,

-- Quantity fields
@Semantics.unitOfMeasure: true
meins,
@Semantics.quantity.unitOfMeasure: 'meins'
quantity

UI Annotations (Fiori Elements)

@UI.lineItem: [{ position: 10 }]
@UI.identification: [{ position: 10 }]
@UI.selectionField: [{ position: 10 }]
field1,

@UI.hidden: true
internal_field

Consumption Annotations (Value Help)

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

For complete annotation reference, see references/annotations-reference.md.

3. Expressions and Operations

CASE Expressions

Simple CASE (single variable comparison):

case status
  when 'A' then 'Active'
  when 'I' then 'Inactive'
  else 'Unknown'
end as StatusText

Searched CASE (multiple conditions):

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

Comparison Operators

Standard operators: =, <>, <, >, <=, >=

Special operators: BETWEEN x AND y, LIKE, IS NULL, IS NOT NULL

Complete Reference: See references/expressions-reference.md for all operators and expressions.

Arithmetic Operations

quantity * price as TotalAmount,
amount / 100 as Percentage,
-amount as NegatedAmount

Session Variables

Available system variables (SY fields equivalent):

$session.user (SY-UNAME) - Current user [7.40 SP08+]
$session.client (SY-MANDT) - Client [7.40 SP08+]
$session.system_language (SY-LANGU) - Language [7.40 SP08+]
$session.system_date (SY-DATUM) - Current date [7.51+]

> Note: $session.user/client/system_language are available from 7.40 SP08.

> $session.system_date requires 7.51+. @Environment.systemField requires 7.50+.

Complete Reference: See references/expressions-reference.md for all system variables.

$session.user as CurrentUser,
$session.system_date as Today

4. Built-in Functions

CDS provides comprehensive built-in functions for string, numeric, and date operations.

Key Function Categories

String Functions: concat(), length(), substring(), upper(), lower(), replace()
Numeric Functions: abs(), ceil(), floor(), round(), division()
Date Functions: dats_add_days(), dats_add_months(), dats_days_between()
CAST Expression: Convert between ABAP data types

> Note: upper() and lower() in CDS require 7.51+. On 7.40/7.50, case

> conversion must be performed in ABAP after selecting (there is no CDS equivalent).

Complete Reference: See references/functions-reference.md for all 50+ functions with examples.

Quick Examples

-- String operations
concat(first_name, last_name) as FullName,
upper(name) as UpperName,
substring(description, 1, 10) as ShortDesc

-- Numeric operations  
abs(amount) as AbsoluteAmount,
round(value, 2) as RoundedValue,
division(10, 3, 2) as PreciseDivision

-- Date operations
dats_add_days(current_date, 7) as NextWeek,
dats_days_between(start_date, end_date) as Duration

-- Type conversion
cast(field as abap.char(10)) as TextField,
cast(amount as abap.curr(15,2)) as CurrencyField

**ABAP Types**: `abap.char()`, `abap.numc()`, `abap.int4`, `abap.dats`, `abap.tims`, `abap.curr()`, `abap.cuky`, `abap.quan()`, `abap.unit()`

---

## 5. Joins

### Join Types

-- INNER JOIN (matching rows only)

inner join makt as t on m.matnr = t.matnr

-- LEFT OUTER JOIN (all from left, matching from right)

left outer join marc as c on m.matnr = c.matnr

-- RIGHT OUTER JOIN (all from right, matching from left) -- [7.51+]

right outer join mvke as v on m.matnr = v.matnr

-- CROSS JOIN (cartesian product) -- [7.51+]

cross join t001 as co


---

## 6. Associations

Associations define relationships between entities (join-on-demand):

### Defining Associations

define view Z_ASSOC_EXAMPLE as select from scarr as c

association [1..*] to spfli as _Flights

on $projection.carrid = _Flights.carrid

association [0..1] to sairport as _Airport

on $projection.hub = _Airport.id

{

key c.carrid,

c.carrname,

c.hub,

// Expose associations

_Flights,

_Airport

}


### Cardinality Notation

**Syntax mapping**:
- `[0..1]` or `[1]` → `association to one` (LEFT OUTER MANY TO ONE)
- `[1..1]` → `association to one` (exact match)
- `[0..*]` or `[*]` → `association to many` (LEFT OUTER MANY TO MANY)
- `[1..*]` → `association to many` (one or more)

**Complete Reference**: See `references/associations-reference.md` for detailed cardinality guide.

### New Cardinality Syntax (Release 2302+)

association to one _Customer on ... -- [0..1]

association to many _Items on ... -- [0..*]


### Using Associations

-- Expose for consumer use

_Customer,

-- Ad-hoc field access (triggers join)

_Customer.name as CustomerName


### Path Expressions with Filter

-- Filter with cardinality indicator

_Items[1: Status = 'A'].ItemNo


For complete association reference, see `references/associations-reference.md`.

---

## 7. Input Parameters

### Defining Parameters

define view Z_PARAM_EXAMPLE

with parameters

p_date_from : dats,

p_date_to : dats,

@Environment.systemField: #SYSTEM_LANGUAGE

p_langu : spras

as select from vbak as v

{

key v.vbeln,

v.erdat,

v.erzet

}

where v.erdat between :p_date_from and :p_date_to


### Parameter Reference
Use colon notation `:p_date_from` or `$parameters.p_date_from`

**Calling from ABAP**:

SELECT * FROM z_param_example(

p_date_from = '20240101',

p_date_to = '20241231',

p_langu = @sy-langu

) INTO TABLE @DATA(lt_result).


---

## 8. Aggregate Expressions

### Aggregate Functions

define view Z_AGG_EXAMPLE as select from vbap as i

{

i.vbeln,

sum(i.netwr) as TotalAmount,

avg(i.netwr) as AvgAmount,

max(i.netwr) as MaxAmount,

min(i.netwr) as MinAmount,

count(*) as ItemCount

}

group by i.vbeln

having sum(i.netwr) > 1000


---

## 9. Access Control (DCL)

### Basic DCL Structure

@MappingRole: true

define role Z_CDS_EXAMPLE_DCL {

grant select on Z_CDS_EXAMPLE

where (bukrs) = aspect pfcg_auth(F_BKPF_BUK, BUKRS, ACTVT = '03');

}


### Authorization Check Options

**Available values**:
- `#NOT_REQUIRED` - No authorization check
- `#CHECK` - Warning if no DCL exists
- `#MANDATORY` - Error if no DCL exists
- `#NOT_ALLOWED` - DCL ignored if exists

**Complete Reference**: See `references/access-control-reference.md` for detailed DCL patterns.

### Condition Types

**PFCG Authorization**: `where (field) = aspect pfcg_auth(AUTH_OBJECT, AUTH_FIELD, ACTVT = '03')`

**Literal Condition**: `where status <> 'DELETED'`

**User Aspect**: `where created_by ?= aspect user`

**Combined**: `where (bukrs) = aspect pfcg_auth(...) and status = 'ACTIVE'`

For complete access control reference, see `references/access-control-reference.md`.

---

## 10. Data Retrieval from ABAP

### Standard SELECT

SELECT * FROM zcds_example

WHERE field1 = @lv_value

INTO TABLE @DATA(lt_result).


### SALV IDA (Integrated Data Access)

cl_salv_gui_table_ida=>create_for_cds_view(

CONV #( 'ZCDS_EXAMPLE' )

)->fullscreen( )->display( ).


---

## 11. Common Errors and Solutions

### SD_CDS_ENTITY105: Missing Reference Information

**Problem**: CURR/QUAN fields without reference

**Solution**: Add semantics annotations

@Semantics.currencyCode: true

waers,

@Semantics.amount.currencyCode: 'waers'

netwr


Or import currency from related table:

inner join t001 as c on ...

{

c.waers,