Why Did CDS DDIC based View get deprecated ? CDS View VS CDS View Entity

We can see clear message from SAP that CDS DDIC based views are obsolete, use a template for CDS view entity instead.

CDS DDIC based views are still supported but SAP will not release any new feature.

Lets understand the difference between CDS DDIC based view and CDS view entity. Below are Key differences .

1. No More ABAP Dictionary View: There’s no DDIC view. The annotation @AbapCatalog.sqlViewName is not required and each view has only one name.

A view entity has an SQL view on the database, but now the intermediate DDIC view is not needed any more. CDS View Entity will only generate a Runtime Object, but not an additional SQL View anymore.

Since CDS view entity will only generate runtime object that leads to fewer potential inconsistencies or confusions about different names and faster object activation because of less dependencies.

2. Annotations

• The element annotations @Semantics.currencyCode? and @Semantics.unitOfMeasure are not supported anymore in a CDS View Entity,
• Instead @Semantics.amount.currencyCode and @Semantics.quantity.unitOfMeasure shall be used. Previously this specification was optional, but it’s now mandatory for data types CURR or QUAN.

• The Annotations @ClientHandling.type and @ClientHandling.algorithm are not supported anymore because the client is now handled automatically, to reduce complexity and development effort.

• The view entity doesn't require the annotation @AbapCatalog.compiler.compareFilter: true,?because the filter is implicitly and automatically compared.

• The view entity doesn't require the annotation @ClientHandling.algorithm, since client handling takes place implicitly.

• The view entity doesn't require the annotation @AbapCatalog.preserveKey: true, because there's no ABAP Dictionary view attached to a CDS view entity.

3. Strict syntax check

Now we have strict syntax check in CDS view entity . Earlier any annotations could be added, even if it was wrongly defined or did not exist at all. Now a check makes sure that the annotation is valid to ensure the desired behavior.

We have added a wrong/meaningless annotation @semantics.false:true (this does not exists at all) in CDS-DDIC based view and CDS Entity View.

There is no error raised in CDS-DDIC based view .

4 . Unsupported Scenarios

CDS View Entity does not support DDIC database views or DDIC external views anymore. This means it’s not possible to select, join or associate with such view types.

Both CDS View and new CDS View Entity may be used in parallel. However, going forward only the CDS View Entity should be created, because it offers several improvements and even lifts some of the previous technical limitations.

A migration of the existing legacy CDS Views is not mandatory but recommended. Automatic conversion tools are available, also see: For more information.

Link of Reference