External Views - ABAP Keyword Documentation

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External Views

An external view is a special view in ABAP Dictionary that defines an SAP HANA View in SAP HANA XSC in ABAP programs. The structure type defined using the view fields of an external view can be referenced in ABAP programs using TYPE. An external view can be specified as a source in Open SQL read statements

External views can only be created using the ABAP Development Tools (ADT) and only if the current database is an SAP HANA database. The SAP HANA view must exist in the SAP HANA repository in SAP HANA XSC. For SAP HANA views in SAP HANA XSA, no external views can be defined in ADT.

When an external view is activated, an alias with the name of the view is created on the SAP HANA database that points to the SAP HANA view. The names of the view fields of the external view can be defined differently from the names of the view fields of the SAP HANA view. The runtime object of the external view accesses the alias on the SAP HANA database. This performs a mapping of HANA-specific data types to the built-in types in ABAP Dictionary. The following table lists the currently supported HANA-specific data types and indicates which ABAP Dictionary types they are mapped to by default.

HANA Type	Meaning	Type in ABAP Dictionary
SMALLINT	2-byte integer	INT2
INTEGER	4-byte integer	INT4
BIGINT	8-byte integer	INT8
DECIMAL	Packed number	DEC
SMALLDECIMAL	Packed number	DEC
FLOAT	Binary floating point number	FLTP
NVARCHAR	Unicode character string	CHAR
VARBINARY	Byte string	RAW
BLOB	Byte string	RAWSTRING
NCLOB	Unicode character string	STRING

External views can be displayed in the ABAP Dictionary tool in the SAP GUI-based ABAP Workbench, but not edited.

An external view can only be read using Open SQL if an SAP HANA database is being accessed in which the associated SAP HANA view exists. If not, the non-handleable exception DBSQL_TABLE_UNKNOWN is raised. External views can exist actively and be used as data types in a system whose standard database is not an SAP HANA database. Views of this type cannot, however, be accessed through the standard connection using Open SQL, only through a secondary connection to an SAP HANA database. Conversely, when an SAP HANA view in an SAP HANA database is accessed through a secondary connection in the current system, only an identically named database table or a structure suitable for any view in ABAP Dictionary can exist actively in ABAP Dictionary.

Notes

The following restrictions currently apply to the use of external views in ABAP programs:

The structure of analytic views do not allow them to be read using SELECT *. The same basic rules apply to the statement SELECT in Open SQL as when using the HANA-SQL statement SELECT, with individual columns and the addition GROUP BY needing to be specified. If SELECT * is used, a runtime error occurs.

Calculation views with parameters can be access only if a default value is defined for each parameter. If not, reads are canceled and produce a runtime error.

External views should only be used in those cases that are not covered by ABAP CDS or AMDP.

For SAP HANA views in SAP HANA XSA, other methods must be used such as AMDP or ADBC.