Description

The standard operation create can be reused in a projection or interface BDEF.

In a projection BDEF, the following additions can be added. Both of them require an implementation in an ABAP behavior pool.

• augment
• precheck

Example: see above, projection BDEF DEMO_RAP_PROJECTION_CRUD.

Description

The standard operation update can be reused in a projection or interface BDEF.

In a projection BDEF, the following additions can be added. Both of them require an implementation in an ABAP behavior pool.

• augment
• precheck

Example: see above, projection BDEF DEMO_RAP_PROJECTION_CRUD.

Description

The standard operation delete can be reused in a projection or interface BDEF.

In a projection BDEF, the following addition can be added. It requires an implementation in an ABAP behavior pool.

• precheck

Example: see above, projection BDEF DEMO_RAP_PROJECTION_CRUD.

Description

The transactional enabling of associations can be reused in a projection or interface BDEF.

If RAP draft handling is enabled in the projection or interface BDEF, associations must be draft enabled using the syntax addition with draft.

Example: use association _assoc { create; with draft; }

For details on the read-by-association and create-by-association operations as well as draft-enabling of associations, see topic RAP - Operations for Associations.

In projection BDEFs, the following additions can be added. Both of them require an implementation in an ABAP behavior pool.

• augment
• precheck

Example: see above, projection BDEF DEMO_RAP_PROJECTION_CRUD.

Description

The syntax element use action can be used in a projection or interface BDEF to project actions, draft actions, and determine actions from the underlying base BDEF. As a prerequisite for reuse, the respective actions, draft actions, and determine actions must be defined in the underlying behavior definition. If an authorization concept or feature control is specified for an action, this is automatically passed on to the projection or interface.

Additions:

• precheck: A precheck can newly be added in the projection layer. An implementation in an ABAP behavior pool is required.
• RedefinedParameter: The input or the output parameter of an action can be redefined in a projection or interface BDEF. For details, see RAP - RedefinedParameter.
• result entity: If the base BDEF specifies an output parameter entity OutputParameter using the keyword result entity, the projection BDEF must specify the projection of the result entity with the syntax result entity ProjResultEntity. Otherwise, it may happen that the action is no longer exposed if the result entity is not included in the service.
• as: An action can be given a new alias name in the projection layer using the keyword as.
• external: A new alias name for external usage in OData can be provided in the projection layer. This external name can be much longer than the alias name in ABAP and needs to be used when defining the corresponding UI annotations.
• result external: A new alias name for the result entity can be provided in the projection layer. This new name is exposed in the OData metadata.

Example

The following example shows a projection BDEF that reuses the two actions Approve_Order and Reject_Order from the underlying base BDEF. The underlying base BDEF is DEMO_CDS_PURCH_DOC_M.

For a detailed description of the definition and implementation of the base BO, see topic RAP - Action.

projection;
strict(2);

define behavior for DEMO_RAP_PROJ_ACTION
{
  use create;
  use update;
  use delete;

  use action Approve_Order as Approve;

  use action Reject_Order as Reject;
}

The ABAP class CL_DEMO_RAP_PROJ_ACTION uses EML to access a RAP business object. It performs the action Reject on one entity instance.

Result: column Status of the respective instance is filled with R for Rejected.

Example

An example for reusing draft actions is shown under Variant 7, use draft.

Description

The syntax element use function can be used in a projection or interface BDEF to reuse functions from the underlying base BDEF. As a prerequisite for reuse, the respective functions must be specified in the underlying behavior definition.

Additions:

• RedefinedParameter: The input or the output parameter of a function can be redefined in a projection or interface BDEF. For details, see RAP - RedefinedParameter.
• result entity: If the base BDEF specifies an output parameter entity OutputParameter using the keyword result entity, the projection BDEF must specify the projection of the result entity with the syntax result entity ProjResultEntity. Otherwise, it may happen that the function is no longer exposed if the result entity is not included in the service.
• as: A function can be given a new alias name in the projection layer using the keyword as.
• external: A new alias name for external usage in OData can be provided in the projection layer. This external name can be much longer than the alias name in ABAP and needs to be used when defining the corresponding UI annotations.
• result external: A new alias name for the result entity can be provided in the projection layer. This new name is exposed in the OData metadata.

The following special rules apply to RAP key functions:

• Reuse is possible in interface and projection BDEFs.
• As a prerequisite for reusing a key function, the alternative key it refers to must be reused using the syntax use key KeyName.
• Key functions are reused using the syntax use function Name. An alias name can be defined using as and an external name can be defined using external. No other additions are possible.

Example

The following example shows a projection BDEF that reuses the functions getDetails, calculateTotal, and calculateDiscount from the underlying base BDEF. The underlying base BDEF is DEMO_RAP_PROJ_FUNCTION.

For a detailed description of the definition and implementation of the base BO, see topic RAP - function.

projection;
strict(2);

define behavior for DEMO_RAP_PROJ_FUNCTION
{
  use create;
  use update;
  use delete;

  use function getDetails;
  use function calculateTotal;
  use function calculateDiscount;
}

The ABAP class CL_DEMO_RAP_PROJ_FUNCTION uses EML to access a RAP business object. It executes all three functions and displays the content of their result structures. No modify operations are carried out, the functions merely deliver information in their result structure without changing database entries.

Result:

Description

RAP draft handling can be reused with the syntax element use draft. As a prerequisite, the underlying RAP BO must be draft-enabled. The draft tables, draft query views (if specified), and the total ETag field are implementation details that are automatically reused and do not have to be explicitly specified in projection BDEFs and interface BDEFs. For details on RAP draft handling, see topic RAP BDL - with draft.

If RAP draft handling is reused, it is mandatory to explicitly reuse the draft actions using the syntax use action in projections BDEFs and RAP BO interfaces.

Reused associations should be explicitly draft-enabled using the syntax element with draft.

Example: use association _assoc { create; with draft; }

For further details on draft-enabled associations, see the topic RAP BDL - operations for associations.

Example

The following example shows a projection BDEF that is based on the unmanaged, draft-enabled BDEF  DEMO_RAP_UNMANAGED_DRAFT_ROOT. It reuses the RAP draft handling.

For a detailed description of the definition and implementation of the base BO, see the topic RAP BDL - with draft.

projection;
strict(2);
use draft;

define behavior for DEMO_RAP_PROJECTION_DRAFT
{
  use create;
  use update;
  use delete;

  use association _child { create; with draft; }

  use action Edit;
  use action Activate;
  use action Discard;
  use action Prepare;
  use action Resume;
}

define behavior for DEMO_RAP_PROJECTION_DRAFT_CHIL
{
  use update;

  use association _parent { with draft; }
}

The implementation is automatically reused from the base BO.

The ABAP class CL_DEMO_RAP_PROJECTION_DRAFT accesses the business object using EML and performs the following steps:

• It creates two new draft instances of the parent entity and two new draft instances of the child entity and displays the content of the draft tables.
• Then it activates the draft entities using the draft action Activate. The content of the draft tables is written to the persistent tables and the draft tables are emptied.

Description

If the base BO specifies RAP ETag fields, these fields can be reused. The keyword use etag must be specified for each entity in the projection or interface BDEF individually. If it is not specified explicitly in the projection or interface BDEF, the optimistic concurrency control functionality is lost.

Further Information

Development guide for the ABAP RESTful Application Programming Model, section Optimistic Concurrency Control.

Description

RAP business events can be reused in an interface BDEF.

Caution: Reuse is possible in interface BDEFs only. It is not possible to reuse a business event in a projection BDEF.

Additions:

• RedefinedParameter: The input parameter of an event can be redefined in the interface BDEF. For details, see RAP - RedefinedParameter.
• The optional addition as can be used to assign an alias name to the business event in question.

Description

RAP side effects can be reused in a projection BDEF and in an interface BDEF.

The syntax use side effects is specified in the behavior definition header and all side effects from all RAP BO entities of the underlying RAP BO are reused. However, if side effects are defined for BO properties, such as fields or actions, that do not appear in the projection at all, these side effects are filtered out and do not have any effect in the projection.

Note: If a base BO is defined as extensible, the syntax use side effects must be specified in the behavior definition header of an interface BDEF or of a projection BDEF to ensure that side effects are reused, even if they are specified in an extension. Otherwise, a syntax check warning occurs.

Example

The following example shows an interface BDEF that reuses the side effects from its underlying base BDEF. The base BDEF is DEMO_RAP_SIDE_EFFECTS.

interface;
use draft;
use side effects;

define behavior for DEMO_RAP_SIDE_EFFECTS_I alias Root
{
  use create;
  use update;
  use delete;

  use action MyActionFC;
  use action MyAction;
  use action someDetermineAction;

  use action Edit;
  use action Activate;
  use action Discard;
  use action Resume;
  use action Prepare;
}

Description

BDEF alternative keys can be reused in a projection or interface BDEF. Optionally, an alias name AliasName can be specified using the addition as. The reused alternative key can then be used to define a new key function in a projection BDEF or for accessing an internal table using this alternative key.

Description

Default values functions can be reused in a projection BDEF or in an interface BDEF. Both the operation in question and the default values function must be reused separately. For details, see the topic RAP - use DefaultValuesFunction.