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ABAP CDS - cast_expr

Syntax

... CAST( operand AS dtype [PRESERVING TYPE]) ...

Effect

Casting in a SELECT statement of a CDS view. The cast expression converts the value of the operand operand to the dictionary type specified by dtype. The result has the type dtype. The following can be specified for dtype:

The following table shows the syntax for specifying built-in data types:

dtype Dictionary Type
abap.char( len ) CHAR with length len
abap.clnt[(3)] CLNT
abap.cuky( len ) CHAR with length len
abap.curr(len,decimals) CURR with length len and decimals decimal places
abap.dats[(8)] DATS
abap.dec(len,decimals) DEC with length len and decimals decimal places
abap.fltp[(16,16)] FLTP
abap.int1[(3)] INT1
abap.int2[(5)] INT2
abap.int4[(10)] INT4
abap.int8[(19)] INT8
abap.lang[(1)] LANG
abap.numc( len ) NUMC with length len
abap.quan(len,decimals) QUAN with length len with decimals decimal places
abap.raw(len) RAW
abap.sstring(len) SSTRING
abap.tims[(6)] TIMS
abap.unit( len ) CHAR with length len

The actual length of the result is defined when the CDS view is activated and is must be at least as long as an explicitly defined length len. The predefined values can be specified for types with fixed lengths and decimal places, but this is not mandatory.

The following can be specified for operand:

Cast expressions can be specified in the SELECT list and in operand positions of expressions.

The following table shows which combinations of built-in data types in ABAP Dictionary can currently be cast to each other and what the prerequisites are in each case. There is a special list of conversion rules for every combination.

from/to INT1 INT2 INT4 INT8 DEC CURR QUAN FLTP CHAR SSTRING NUMC DATS TIMS ACCP CLNT LANG UNIT CUKY RAW
INT1 x x x x y y y x y y - - - - x - - - -
INT2 x x x x y y y x y y - - - - - - - - -
INT4 x x x x y y y x y y - - - - - - - - -
INT8 x x x x y y y x y y - - - - - - - - -
DEC - - - - x x x x y y - - - - - - - - -
CURR - - - - x x x x y y - - - - - - - - -
QUAN - - - - x x x x y y - - - - - - - - -
FLTP - - - - - - - x - - - - - - - - - - -
CHAR - - - - - - - - x x y y y p y y y y -
SSTRING - - - - - - - - x x y y y p y y y y -
NUMC y y y y x x y x y y z z z p z - - - -
DATS - - - - - - - - y y - z - - - - - - -
TIMS - - - - - - - - y y - - z - - - - - -
ACCP - - - - - - - - z z z - - p - - - - -
CLNT - - - - - - - - d d - - - - p - - - -
LANG - - - - - - - - d d - - - - - p - - -
UNIT - - - - - - - - d d - - - - - - p - -
CUKY - - - - - - - - d d - - - - - - - p -
RAW - - - - - - - - - - - - - - - - - - p

There are no further restrictions to note in combinations using "x". The following rules apply to the other combinations:

In the case of incompatible types, the content of the operand is converted to the target type (exceptions can be raised if values are not suitable). In compatible types, a syntax check warning occurs (unless the target data type is specified as a data element using the addition PRESERVING TYPE).

Notes

Example

Cast expressions in a SELECT list.

@AbapCatalog.sqlViewName: 'SALES_ORDER_VW'
define view sales_order as
  select from snwd_so
         association [1..*] to snwd_so_i as _item
           on snwd_so.node_key = _item.parent_key
         { key snwd_so.node_key,
               gross_amount as original_amount,
               cast(gross_amount as abap.fltp) +
                 (cast( -gross_amount as abap.fltp) * 0.03)
                   as reduced_amount,
               cast(gross_amount as abap.fltp) * 0.03
                 as overall_savings,
               _item.so_item_pos as item_position,
               _item.gross_amount as item_gross_amount,
               cast(_item.gross_amount as abap.fltp) * 0.97
                 as item_savings }

Example

In the following view, the column char1 of the database DEMO_EXPRESSIONS is cast to the data element demo_char_text with the same technical attributes. In this case, it is advisable to specify the addition PRESERVING TYPE.

@AbapCatalog.sqlViewName: 'DEMO_CDS_CAST_DE'
@AccessControl.authorizationCheck: #NOT_REQUIRED
define view demo_cds_cast_data_element
as select from
demo_expressions
{
cast ( char1 as DEMO_CHAR_TEXT preserving type) as char_with_text
};    

The following function module call returns the attributes of the view field The text shows that the semantic attributes of the data element were applied. The column char1 does not have its own text.

DATA dfies_tab TYPE TABLE OF dfies.
CALL FUNCTION 'DDIF_FIELDINFO_GET'
  EXPORTING
    tabname   = 'DEMO_CDS_CAST_DE'
    fieldname = 'CHAR_WITH_TEXT'
    langu     = sy-langu
                TABLES
                dfies_tab = dfies_tab.
cl_demo_output=>display( dfies_tab[ 1 ]-fieldtext ).

Example

In the following view, a literal is given the technical and semantic attributes of the data element S_MANDT.

@AbapCatalog.sqlViewName: 'DEMO_CDS_CSTCLNT'
@AccessControl.authorizationCheck: #NOT_REQUIRED
define view demo_cds_cast_clnt
as select from
scarr
{
key cast ( 'XXX' as s_mandt )
as pseudo_client,
key carrid,
carrname
};    


Continue
ABAP CDS - cast_expr, Conversion Rules