Lesson 18 Companion — RAP Compositions

This companion supports:

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Lesson 18 — RAP Compositions: Parent/Child Business Objects

Reference scenario:

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Reservation
└── Participants

1. Core Composition Pattern

Parent:

abap

composition [0..*] of ZR_Reservation_Part_### as _Participants

Child:

abap

association to parent ZR_Reservation_### as _Reservation
  on $projection.ReservationUuid = _Reservation.Uuid

A RAP composition expresses:

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whole
+
dependent part

2. Composition Rules

For this two-node BO:

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exactly one root
root = Reservation
child = Participant
root can be composition source
child defines one direct to-parent association
child cannot exist without parent

3. Child Persistence Reference

abap

@EndUserText.label : 'Reservation Participants'
@AbapCatalog.enhancement.category : #NOT_EXTENSIBLE
@AbapCatalog.tableCategory : #TRANSPARENT
@AbapCatalog.deliveryClass : #A
@AbapCatalog.dataMaintenance : #RESTRICTED

define table zrespart_### {

  key client                 : abap.clnt not null;
  key participant_uuid       : sysuuid_x16 not null;

  reservation_uuid           : sysuuid_x16 not null;
  participant_no             : abap.numc(4);
  participant_name           : abap.char(60);
  participant_email          : abap.char(100);
  participant_role           : abap.char(40);

  local_last_changed_at      : abp_locinst_lastchange_tstmpl;

}

Use the exact table annotation style already established in the course if your existing table templates differ slightly.

4. Why Two UUID Fields

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ParticipantUuid
→ identifies one Participant

ReservationUuid
→ identifies its parent Reservation

One Reservation may own many Participant UUIDs.

5. Child CDS Reference

abap

@AccessControl.authorizationCheck: #CHECK
@EndUserText.label: 'Reservation Participant'

define view entity ZR_Reservation_Part_###
  as select from zrespart_### as Participant

  association to parent ZR_Reservation_### as _Reservation
    on $projection.ReservationUuid = _Reservation.Uuid

{
      _Reservation,

  key Participant.participant_uuid      as ParticipantUuid,
      Participant.reservation_uuid      as ReservationUuid,
      Participant.participant_no        as ParticipantNo,
      Participant.participant_name      as ParticipantName,
      Participant.participant_email     as ParticipantEmail,
      Participant.participant_role      as ParticipantRole,

      @Semantics.systemDateTime.localInstanceLastChangedAt: true
      Participant.local_last_changed_at as LocalLastChangedAt
}

6. To-Parent Association Requirements

The ON condition must identify the parent through its full key.

For this BO:

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parent key = Uuid

Therefore:

abap

$projection.ReservationUuid = _Reservation.Uuid

is complete.

Expose:

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_Reservation

exactly once.

7. Root CDS Addition

Add:

abap

composition [0..*] of ZR_Reservation_Part_### as _Participants

and expose:

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_Participants

in the root select list.

8. Base Child DCL Reference

abap

@EndUserText.label: 'Reservation Participant Access'
@MappingRole: true

define role ZR_Reservation_Part_###
{
  grant select on ZR_Reservation_Part_###
    where ( _Reservation.ResponsibleUser ) = aspect user;
}

The child read policy follows parent ownership.

9. Root Behavior Addition

Inside the root behavior:

abap

association _Participants { create; with draft; }

This enables:

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read related children
create child through parent
same-state draft navigation

10. Child Behavior Reference

abap

define behavior for ZR_Reservation_Part_### alias Participant
persistent table zrespart_###
draft table zdrespart_###
authorization dependent by _Reservation
lock dependent by _Reservation
etag master LocalLastChangedAt
{
  update;
  delete;

  field ( numbering : managed, readonly )
    ParticipantUuid;

  field ( readonly )
    ReservationUuid,
    LocalLastChangedAt;

  field ( mandatory:create, readonly:update )
    ParticipantNo;

  association _Reservation { with draft; }

  mapping for zrespart_###
  {
    ParticipantUuid    = participant_uuid;
    ReservationUuid    = reservation_uuid;
    ParticipantNo      = participant_no;
    ParticipantName    = participant_name;
    ParticipantEmail   = participant_email;
    ParticipantRole    = participant_role;
    LocalLastChangedAt = local_last_changed_at;
  }
}

11. Why No Standard Child Create

In managed RAP:

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root
→ CREATE

child
→ CREATE BY association

The child itself does not expose independent root-style create.

12. Lock Dependency

abap

lock dependent by _Reservation

means:

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modify child
→ find parent
→ use parent lock master

Only root entities are lock masters in this managed BO design.

13. Authorization Dependency

abap

authorization dependent by _Reservation

means the child's standard modifying operations use the parent authorization master.

For the current course:

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parent ownership
→ child modifying permission

14. Child ETag

Use:

abap

etag master LocalLastChangedAt

The child can be its own ETag master while lock and authorization remain dependent on the root.

15. Root Total ETag

The root:

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LastChangedAt

remains the total ETag.

A total ETag covers:

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the complete BO composition tree

With correct managed annotations and mapping:

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active child change
→ root total ETag changes

16. Child Draft Table

Declare:

abap

draft table zdrespart_###

Then:

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Ctrl+1
→ Create draft table

Use generated draft persistence.

Do not manually write technical draft columns.

17. Draft Association Contract

Root:

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association _Participants { create; with draft; }

Child:

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association _Reservation { with draft; }

Draft-enabled BO-internal associations always navigate to the same active/draft state.

18. Create-by-Association Reference

abap

MODIFY ENTITIES OF ZR_Reservation_###
  ENTITY Reservation
    CREATE BY \_Participants
      FIELDS (
        ParticipantNo
        ParticipantName
        ParticipantEmail
        ParticipantRole
      )
      WITH VALUE #(
        (
          Uuid = reservation_uuid
          %target = VALUE #(
            (
              %cid             = 'PART-001'
              ParticipantNo    = '0001'
              ParticipantName  = 'Taylor Reed'
              ParticipantEmail = 'taylor@example.com'
              ParticipantRole  = 'Attendee'
            )
          )
        )
      )
  MAPPED DATA(mapped)
  FAILED DATA(failed)
  REPORTED DATA(reported).

19. `%target`

Each CBA source row contains:

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parent identity
+
%target

%target is the nested child-create table.

20. Managed Child Numbering

The external consumer does not fill:

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ParticipantUuid

It supplies:

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%cid

and reads the generated UUID from:

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MAPPED-Participant

21. Read-by-Association Reference

abap

READ ENTITIES OF ZR_Reservation_###
  ENTITY Reservation
    BY \_Participants
      ALL FIELDS
      WITH VALUE #(
        ( Uuid = reservation_uuid )
      )
    RESULT DATA(participants)
    LINK DATA(participant_links)
    FAILED DATA(failed_read).

22. `LINK`

LINK returns the relationship between:

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source parent key
target child key

It is useful when several source parents are read together.

23. Deep Create Reference

abap

MODIFY ENTITIES OF ZR_Reservation_###
  ENTITY Reservation
    CREATE FIELDS (
      ReservationNo
      CustomerName
      ReservationDate
      Fee
      CurrencyCode
    )
    WITH VALUE #(
      (
        %cid            = 'ROOT-001'
        ReservationNo   = '99180001'
        CustomerName    = 'Composition Student'
        ReservationDate = cl_abap_context_info=>get_system_date( )
        Fee              = '450.00'
        CurrencyCode     = 'EUR'
      )
    )

    CREATE BY \_Participants
      FIELDS (
        ParticipantNo
        ParticipantName
      )
      WITH VALUE #(
        (
          %cid_ref = 'ROOT-001'
          %target = VALUE #(
            (
              %cid            = 'CHILD-001'
              ParticipantNo   = '0001'
              ParticipantName = 'Morgan Lee'
            )
          )
        )
      )

  MAPPED DATA(mapped)
  FAILED DATA(failed)
  REPORTED DATA(reported).

24. `%cid_ref`

Use:

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%cid_ref

when the parent is created in the same EML request.

It references the parent's temporary:

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%cid

before the final managed key is available.

25. Child Projection Reference

abap

@AccessControl.authorizationCheck: #CHECK
@EndUserText.label: 'Reservation Participant Projection'
@Metadata.allowExtensions: true

define view entity ZC_Reservation_Part_###
  as projection on ZR_Reservation_Part_###
{
  key ParticipantUuid,
      ReservationUuid,
      ParticipantNo,
      ParticipantName,
      ParticipantEmail,
      ParticipantRole,
      LocalLastChangedAt,

      _Reservation : redirected to parent ZC_Reservation_###
}

26. Root Projection Redirection

Add to:

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ZC_RESERVATION_###

abap

_Participants
  : redirected to composition child ZC_Reservation_Part_###

Projection composition targets must be projection entities.

27. Projection Child DCL

abap

@EndUserText.label: 'Reservation Participant Projection Access'
@MappingRole: true

define role ZC_Reservation_Part_###
{
  grant select on ZC_Reservation_Part_###
    where inheriting conditions from entity ZR_Reservation_Part_###;
}

28. Projection Behavior Reference

Root addition:

abap

use association _Participants { create; with draft; }

Child:

abap

define behavior for ZC_Reservation_Part_### alias Participant
use etag
{
  use update;
  use delete;

  use association _Reservation { with draft; }
}

29. Why No New Behavior Pool

The child belongs to the existing managed BO.

Standard managed behavior is provided by the RAP runtime.

A new custom handler is only needed when the child gains custom:

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validation
determination
action
feature control

30. Service Definition Reference

abap

@ObjectModel.leadingEntity.name: 'ZC_RESERVATION_###'
define service ZUI_RESERVATION_###
{
  expose ZC_Reservation_###      as Reservations;
  expose ZC_Reservation_Part_### as Participants;
  expose I_CurrencyStdVH         as Currencies;
}

All BO projection nodes relevant to the UI service should be exposed.

abap

@UI.facet: [
  {
    id: 'Reservation',
    purpose: #STANDARD,
    type: #IDENTIFICATION_REFERENCE,
    label: 'Reservation',
    position: 10
  },
  {
    id: 'Participants',
    purpose: #STANDARD,
    type: #LINEITEM_REFERENCE,
    label: 'Participants',
    position: 20,
    targetElement: '_Participants'
  }
]

Use #LINEITEM_REFERENCE for a [0..*] child collection.

32. Child Line Items

abap

@Metadata.layer: #CORE

annotate entity ZC_Reservation_Part_### with
{
  @UI.lineItem: [ { position: 10, label: 'Participant No.' } ]
  ParticipantNo;

  @UI.lineItem: [ { position: 20, label: 'Name' } ]
  ParticipantName;

  @UI.lineItem: [ { position: 30, label: 'Email' } ]
  ParticipantEmail;

  @UI.lineItem: [ { position: 40, label: 'Role' } ]
  ParticipantRole;
}

33. Draft Runtime

During an edit draft:

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active root
draft root
active children
draft children

can coexist as active/draft versions of the same BO tree.

A child created in the draft remains in:

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child draft persistence

until activation.

34. One Save Activates the Tree

Fiori Save on the draft root activates:

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root changes
child creates
child updates
child deletes

as one draft BO transaction.

35. Child Read Authorization

Behavior authorization protects modifying operations.

DCL still protects reads.

Therefore protect:

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ZR_RESERVATION_PART_###
ZC_RESERVATION_PART_###

separately from the parent DCL.

36. Troubleshooting CDS

If activation fails:

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create child CDS first
check parent key in ON condition
expose _Reservation once
check composition target name
expose _Participants in root

37. Troubleshooting BDEF

Check:

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child persistent table
child draft table
lock dependent association
authorization dependent association
ETag field
managed UUID field
root association create
with draft on both sides
mapping

38. Troubleshooting Projection

Check:

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child projection exists
root redirects composition to child projection
child redirects parent to root projection
projection BDEF exposes both associations

39. Troubleshooting Service/UI

If child table is missing:

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child exposed in Service Definition?
binding reloaded?
root facet targetElement correct?
child @UI.lineItem present?
projection association create-enabled?

40. Certification Focus

Key repair concepts:

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composition
association to parent
create by association
lock dependent by
authorization dependent by
with draft
%target
%cid_ref
LINK
redirected to composition child
redirected to parent
use association

Students should be able to trace a multi-node BO from persistence to Fiori.

Next steps

Apply Lessons 15–18 to your Purchase Request BO in Project 4 — Service-Ready Purchase Request Application. Complete the checkpoint before continuing with Lesson 19 — RAP Business Events.

Lesson 18 Companion — RAP Compositions ​

1. Core Composition Pattern ​

2. Composition Rules ​

3. Child Persistence Reference ​

4. Why Two UUID Fields ​

5. Child CDS Reference ​

6. To-Parent Association Requirements ​

7. Root CDS Addition ​

8. Base Child DCL Reference ​

9. Root Behavior Addition ​

10. Child Behavior Reference ​

11. Why No Standard Child Create ​

12. Lock Dependency ​

13. Authorization Dependency ​

14. Child ETag ​

15. Root Total ETag ​

16. Child Draft Table ​

17. Draft Association Contract ​

18. Create-by-Association Reference ​

19. %target ​

20. Managed Child Numbering ​

21. Read-by-Association Reference ​

22. LINK ​

23. Deep Create Reference ​

24. %cid_ref ​

25. Child Projection Reference ​

26. Root Projection Redirection ​

27. Projection Child DCL ​

28. Projection Behavior Reference ​

29. Why No New Behavior Pool ​

30. Service Definition Reference ​

31. Parent UI Facet ​

32. Child Line Items ​

33. Draft Runtime ​

34. One Save Activates the Tree ​

35. Child Read Authorization ​

36. Troubleshooting CDS ​

37. Troubleshooting BDEF ​

38. Troubleshooting Projection ​

39. Troubleshooting Service/UI ​

40. Certification Focus ​

Next steps ​

Lesson 18 Companion — RAP Compositions

1. Core Composition Pattern

2. Composition Rules

3. Child Persistence Reference

4. Why Two UUID Fields

5. Child CDS Reference

6. To-Parent Association Requirements

7. Root CDS Addition

8. Base Child DCL Reference

9. Root Behavior Addition

10. Child Behavior Reference

11. Why No Standard Child Create

12. Lock Dependency

13. Authorization Dependency

14. Child ETag

15. Root Total ETag

16. Child Draft Table

17. Draft Association Contract

18. Create-by-Association Reference

19. `%target`

20. Managed Child Numbering

21. Read-by-Association Reference

22. `LINK`

23. Deep Create Reference

24. `%cid_ref`

25. Child Projection Reference

26. Root Projection Redirection

27. Projection Child DCL

28. Projection Behavior Reference

29. Why No New Behavior Pool

30. Service Definition Reference

31. Parent UI Facet

32. Child Line Items

33. Draft Runtime

34. One Save Activates the Tree

35. Child Read Authorization

36. Troubleshooting CDS

37. Troubleshooting BDEF

38. Troubleshooting Projection

39. Troubleshooting Service/UI

40. Certification Focus

Next steps