EXEC SQL - Host Variables
Host variables are global or local variables (usually variables)
declared in the ABAP program that are used in operand positions of
embedded Native SQL statements. For
identification purposes, the data object name has a colon ( : )
directly in front of it. Instead of the data object itself, a field
symbol to which the data object is assigned can be specified.
Dereferenced data reference variables cannot be dereferenced.
Only flat elementary fields and flat structures with elementary
components can be used as host variables, with one
exception . If a structure is listed in a
Native SQL statement after INTO , it is converted by the
Native SQL interface as if its components were listed as individual
fields separated by commas.
In a SELECT statement, the SAP-specific addition STRUCTURE
can be specified between INTO and an individual host
variable. This addition has the effect that the host variable is treated
like a structure, even if a non-typed formal parameter or a non-typed
field symbol is specified. Otherwise, when multiple values are being
passed, depending on the platform, either the first value only is passed
or an exception occurs.
When assignments are made between host variables and fields in
database tables, the Native SQL interface passes a description of
type, size, and storage location of the ABAP data objects used to the
database system. The actual database accesses and conversions are
usually executed directly by the corresponding operations of the
database system. In some cases, however, the Native SQL interface
executes extensive compatibility checks.
Latest notes: The indicator variables provided in the SAP standard, which
can be specified after an operand to identify null values, can be specif
ied in static Native SQL by a host variable that has to be of an
external data type INT2 .
Example ABAP Coding Like the example for literals ;
the row to be read is here also specified using host variables. The
addition STRUCTURE is specified after INTO . However, this
is not necessary since wa can be identified statically as a
structure. The structure wa is handled in the INTO clause
as if all subfields were listed separately:
INTO :wa-cityfrom,
:wa-cityto .
PARAMETERS: p_carrid TYPE spfli-carrid,
p_connid TYPE spfli-connid.
DATA: BEGIN OF wa,
cityfrom TYPE spfli-cityfrom,
cityto TYPE spfli-cityto,
END OF wa.
EXEC SQL.
SELECT cityfrom, cityto
INTO STRUCTURE :wa
FROM spfli
WHERE mandt = :sy-mandt AND
carrid = :p_carrid AND connid = :p_connid
ENDEXEC.
Documentation extract taken from SAP system, � Copyright SAP AG. All rights reserved