Data Types and Variables
ABAP provides a set of built-in data types. In addition, every structure, table, view or data element defined in the ABAP Dictionary can be used to type a variable. Also, object classes and interfaces can be used as types.
The built-in data types are:
| Type | Description |
|---|---|
| I | Integer (4-bytes) |
| P | Packed decimal |
| F | Floating point |
| N | Character numeric |
| C | Character |
| D | Date |
| T | Time |
| X | Hexadecimal (raw byte) |
| STRING | Variable-length string |
| XSTRING | Variable-length raw byte array |
Date variables or constants (type D) contain the number of days since January 1, 1 AD. Time variables or constants (type T) contain the number of seconds since midnight. A special characteristic of both types is that they can be accessed both as integers and as character strings (with internal format "YYYYMMDD" for dates and "hhmmss" for times), which makes date/time handling very easy. For example, the code snippet below calculates the last day of the previous month (note: SY-DATUM is a system-defined variable containing the current date):
DATA LAST_EOM TYPE D. "last end-of-month date * Start from today's date LAST_EOM = SY-DATUM. * Set characters 6 and 7 (0-relative) of the YYYYMMDD string to "01", * giving the first day of the current month LAST_EOM+6(2) = '01'. * Subtract one day LAST_EOM = LAST_EOM - 1. WRITE: 'Last day of previous month was', LAST_EOM.All ABAP variables must be explicitly declared in order to be used. Normally all declarations are placed at the top of the code module (program, subroutine, function) before the first executable statement; this placement is a convention and not an enforced syntax rule. The declaration consists of the name, type, length (where applicable), additional modifiers (e.g. the number of implied decimals for a packed decimal field) and optionally an initial value:
* Primitive types: DATA: COUNTER TYPE I, VALIDITY TYPE I VALUE 60, TAXRATE(3) TYPE P DECIMALS 1, LASTNAME(20) TYPE C, DESCRIPTION TYPE STRING. * Dictionary types: DATA: ORIGIN TYPE COUNTRY. * Internal table: DATA: T_FLIGHTS TYPE TABLE OF FLIGHTINFO, T_LOOKUP TYPE HASHED TABLE OF FLT_LOOKUP. * Objects: DATA: BOOKING TYPE REF TO CL_FLT_BOOKING.Notice the use of the colon to chain together consecutive DATA statements.
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