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ABENCDS_V1_BUFFERING - CDS V1 BUFFERING

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- Table Buffering of CDS DDIC-Based Views

The following CDS annotations can define table buffering for a CDS view linked with a CDS-managed DDIC view:

• @AbapCatalog.buffering.status defines whether and how table buffering is allowed.

• @AbapCatalog.buffering.type determines the buffering type.

• @AbapCatalog.buffering.numberOfKeyFields determines the number of key fields covered if generic buffering is used.

Table buffering of CDS views is done for the associated CDS-managed DDIC view and the same prerequisites apply as for DDIC database views in ABAP Dictionary. To meet these prerequisites, a CDS view can only be buffered if the following applies:

• It cannot contain any views

(DDIC database views or CDS views) and no CDS table functions as data sources.

• It cannot have any input parameters.

• A client-dependent view can use $session.client as the only session variable and must use it directly. This also allows the annotation @ClientHandling.algorithm:#SESSION_VARIABLE to be specified to determine client handling. A client-independent view must not use any session variables.

• Key fields cannot contain null values.

• The required key fields must be listed directly in the SELECT list. Key fields that only occur as arguments of expressions cannot be evaluated.

• No database tables can be accessed where data aging is enabled,

Only the key fields of the CDS-managed DDIC view are respected in SAP buffering of CDS-managed DDIC views. By default, these are not the key elements of the CDS entity defined using KEY (unless the value true is specified for the view annotation AbapCatalog.preserveKey.

Notes

• In client-dependent views, the client column must be explicitly included or added to the number in the specification for the annotation @AbapCatalog.buffering.numberOfKeyFields.

• For CDS view entities, table buffering is defined directly for the CDS entity. A client column is not counted as a key field, there.

• In contrast to table buffering of CDS view entities, where the prerequisites are real restrictions for the view, for DDIC-based views that do not meet the prerequisites buffering is bypassed implicitly by ABAP SQL.

Example

Enables full buffering for a CDS view.

@AbapCatalog.sqlViewName: '...'
@AbapCatalog.Buffering.status: #ACTIVE
@AbapCatalog.Buffering.type: #FULL
  define view ...
   as select from ...
   { ... }

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