What does it do? Defines a CDS simple type in the CDS TDL. A CDS simple type defines an elementary data type natively in ABAP CDS. A CDS simple type can be enriched with CDS annotations type_annot. All annotations are optional and a simple type can also be created without any annotations. If specified, the type annotations must be defined in front of the statement DEFINE TYPE . The name simple_type of the CDS simple type is defined after the DEFINE TYPE statement. It is in the namespace of all global types of an AS ABAP. The general rules for CDS object names described in topic ABAP CDS - General Syntax Rules apply. The name of the CDS simple type must be the same as the name of the TDL source code.
Typing A simple type can be typed as follows:
Using a built-in ABAP Dictionary data type dtype . All possible types and rules are described in the topic CDS Simple Type, dtype.
Using a DDIC data element data_element. The rules, including inheritance rules, are described in topic CDS Simple Type, data_element.
Using another CDS simple type simple_type . The rules are described in topic CDS Simple Type, simple_type.
ABAP_USE CDS simple types can be used in the following places:
To type another CDS simple type. ABAP_NOTE The maximum nesting depth is five. This means that a stack of simple types can have a maximum of five layers, from base to top-most.
In cast expressions in CDS view entities .
In cast expressions in CDS projection views. ABAP_NOTE Remember that casting in CDS projection views is only possible with the addition PRESERVING TYPE. Example: cast(ProjField as MySimpleType preserving type) as NewProjField
For typing of elements in CDS custom entities and in CDS abstract entities.
For typing of parameters in ABAP_CDS_V2_VIEWS , CDS analytical projection views, CDS custom entities, CDS abstract entities, and CDS hierarchies.
For typing of CDS virtual elements in CDS projection views.
For typing the input parameters or the return parameter of SQL-based scalar functions.
In ABAP for typing data objects with the statement TYPE.
ABAP_RESTRICTIONS
CDS simple types cannot be used in ABAP_CDS_V1_VIEWS .
CDS simple types cannot be used for typing in DDIC objects such as DDIC data types, DDIC views, and DDIC extensions.
Unlike DDIC data elements, there is no search help assignment available for CDS simple types.
CDS simple types cannot be used in CDS table functions. ABAP_RESTR_END
Latest notes: If a ABAP_CDS_V1_VIEWS selects from a view entity that is typed with a simple type, then the simple type information is available in the metadata of the CDS entity, but not in the metadata of the CDS-managed DDIC view. NON_V5_HINTS ABAP_HINT_END
ABAP_EXAMPLE_VX5 - Evaluation of Annotations of a Simple Type The following CDS simple type is based on a DDIC data element. DRTY DEMO_SIMPLE_TYPE_DE The semantic information of the data element is inherited to the simple type and translated into annotations. These annotations and their values can be seen in the Active Annotations view in ADT: IMAGE st_active_anno.jpg 756 202 The class CL_DEMO_CDS_SIMPLE_TYPE demonstrates the following:
The data type and length of a CDS simple type can be evaluated using RTTI methods.
The annotations of the CDS simple type can be evaluated using the class CL_DD_DDL_ANNOTATION_SERVICE. ABAP_EXAMPLE_END
ABAP_EXAMPLE_VX5 - Using Simple Types for Typing in a CDS View Entity The following CDS view entity uses a CDS simple type for typing of parameters p1 and p2. It casts element cast_bt into a simple type. DDLS DEMO_CDS_SIMPLE_TYPE_USAGE The following code snippet demonstrates how the metadata of the CDS view entity can be evaluated using the class CL_DD_CDS_READ_API_FACTORY. The tables that are generated as output have columns that indicate whether a field or parameter is typed with reference to a simple type. ABEXA 01752 ABAP_EXAMPLE_END
