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ABENCDS_CAST_EXPRESSION_V2 - CDS CAST EXPRESSION V2

ABENCDS_CAST_EXPRESSION_V2 - CDS CAST EXPRESSION V2

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- CDS View Entity, cast_expr

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

Effect

Casting in a SELECT statement of a CDS view entity. The cast expression converts the value of the operand operand to the ABAP Dictionary type specified by dtype. The result has the type dtype.

The following can be specified for dtype:

  • A DDIC data element. In this case, the optional addition PRESERVING TYPE can be specified. If this addition is specified, the built-in data type, the length of the operand and the number of decimal places, and the target data type must match exactly.
  • A built-in data type in ABAP Dictionary. The addition PRESERVING TYPE cannot be specified in this case.

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$[(5)$] CUKY
abap.curr(len,decimals) CURR with length len and decimals decimal places
abap.decfloat16$[(16)$] DECFLOAT16
abap.decfloat34$[(34)$] DECFLOAT34
abap.dats$[(8)$] DATS
abap.datn$[(8)$] DATN
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.sstring(len) SSTRING
abap.tims$[(6)$] TIMS
abap.timn$[(6)$] TIMN
abap.unit$[(2$|3)$] UNIT with length 2 or 3 (standard length)
abap.utclong$[(27)$] UTCLONG

The actual length of the result is defined when the CDS view entity is activated and is at least as long as an explicitly defined length len. It is possible, but not mandatory, to specify the length for types with fixed lengths and decimal places.

The following can be specified for operand:

  • Another, nested, cast expression

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 DECFLOAT16 DECFLOAT34 FLTP CHAR SSTRING NUMC DATS TIMS DATN TIMN UTCLONG ACCP CLNT LANG UNIT CUKY RAW DF16_DEC DF34_DEC
INT1 x x x x x x x x x x y y - - - - - - - x - - - - - -
INT2 x x x x x x x x x x y y - - - - - - - - - - - - - -
INT4 x x x x x x x x x x y y - - - - - - - - - - - - - -
INT8 x x x x x x x x x x y y - - - - - - - - - - - - - -
DEC x x x x x x x x x x y y - - - - - - - - - - - - - -
CURR x x x x x x x - - x y y - - - - - - - - - - - - - -
QUAN x x x x x x x x x x y y - - - - - - - - - - - - - -
DECFLOAT16 x x x x x - x x x - x - - - - - - - - - - - - - - -
DECFLOAT34 x x x x x - x x x - x - - - - - - - - - - - - - - -
DF16_DEC - - - - - - - x x - - - - - - - - - - - - - - - d -
DF34_DEC - - - - - - - x x - - - - - - - - - - - - - - - - d
FLTP x x x x x x x x x x - - - - - - - - - - - - - - - -
CHAR x x x x x x x x x - x x x x x - - - p x x x x - - -
SSTRING x x x x x x x x x - x x x x x - - - p x x x x - - -
NUMC y y y y x x x x x x x x z z z - - - p z - - - - - -
DATS x x x x x x x x x - x x - z - - - - - - - - - - - -
TIMS x x x x x x x x x - x x - - z - - - - - - - - - - -
DATN - - - - - - - - - - - - - - - x - - - - - - - - - -
TIMN - - - - - - - - - - - - - - - - x - - - - - - - - -
UTCLONG - - - - - - - - - - - - - - - - - x - - - - - - - -
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 with "x". The following rules apply to the other combinations:

  • In combinations with "y", the length of the target data type must be sufficient.
  • In combinations with "z", the lengths of the data types must match exactly.
  • In the case of combinations with "p" or "d", a data element must be specified as the target data type. It is not possible to specify a built-in data type from ABAP Dictionary.
  • In combinations with "d", the data element can have a suitable target type in accordance with the table above and with any length.

  • In combinations with "p", the data element must have the built-in data type and the same length as the data type of the operand.

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). For compatible types, a syntax check warning occurs (unless the target data type is specified as a data element using the addition PRESERVING TYPE).

If the target type dtype is specified as CURR or QUAN, then a Semantics reference annotation specifying a currency key or unit key is mandatory.

Notes

  • If a data element is specified for dtype, the result of the expression inherits the semantic attributes of the data element. An exception to this is the use of the CAST expression within a case distinction.
  • If the addition PRESERVING TYPE is specified, the data type of the operand stays the same and only the semantic attributes are changed.
  • The characters in the surrogate area of the system code page UTF-16 are handled as two characters in cast expressions for strings. Care should be taken to avoid splitting these characters in truncation operations.
  • When performing a conversion between currency fields with type CURR, it should be noted that CAST respects the decimal places defined for the type. In ABAP applications, on the other hand, the position of the decimal point is usually ignored.
  • A CAST expression should be platform-independent. Conversions from the type FLTP to other numeric types are not allowed because the result would be platform-dependent.
  • Special built-in conversion functions are available for conversions that cannot be covered by a CAST expression:

Example

Cast expressions in a SELECT list.

Example

In the following view entity, the column char1 of the DDIC database table 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.

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_DATA_ELEMENT_VE'
    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.






TXBHW - Original Tax Base Amount in Local Currency   SUBST_MERGE_LIST - merge external lists to one complete list with #if... logic for R3up  
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