01 What happened
SAP published a technical guide on field definitions in CDS table entities. Developers can use explicit null for LOB and geodata columns. Client handling is implicit via the @ClientHandling.type annotation; the explicit client field is no longer needed. abap.int1 now maps to HANA TINYINT (classic tables use SMALLINT). Types abap.clnt, abap.dats, abap.tims, abap.accp, abap.lchr, abap.varc, abap.df16_raw, and abap.df34_raw are deprecated.
02 Key details
- Field syntax: field_definition ::= [field_annotation] [key] field_name : type_reference [null]; nullability is officially supported; abap.string, abap.rawstring and abap.geom_ewkb require the null keyword; omitting it causes syntax errors.
- Client dependency is implicit via the @ClientHandling.type annotation; abap.clnt is not supported and the explicit client field is removed.
- abap.int1 maps to TINYINT (classic tables map it to SMALLINT) – the only mapping difference from classic tables; abap.dats and abap.tims are replaced by abap.datn (true DATE) and abap.timn (true TIME); use abap.utclong for timestamps.
- Types DF16_RAW, DF34_RAW, and LCHR are deprecated; DF16_RAW and DF34_RAW require a table conversion to DEC, DECFLOAT16 or DECFLOAT34; LCHR can be replaced by abap.string or abap.sstring; DF16_SCL, DF34_SCL and PREC are obsolete.
- abap.geom_ewkb maps to HANA ST_GEOMETRY; requires SRID via @AbapCatalog.geo.spatialRefSystem (default 0); SRID=NULL allows different values later at a performance cost; cannot be used for key fields and requires the null keyword.
03 Why it matters
Developers creating or migrating to CDS table entities must adopt nullable LOB/geodata types and implicit client handling, and replace deprecated types before they block development or require table conversions. Omitting the null keyword for required types causes activation errors. Deprecated types like DF16_RAW and DF34_RAW may require future table conversions; LCHR should be replaced with abap.string or abap.sstring.
04 Who it matters to
ABAP developers, data architects and SAP HANA administrators.