Generating Transient Program & Persistent Program

*Generating Transient program
DATA : itab TYPE TABLE OF string,
             prog TYPE program,
             msg(120) TYPE c,
             lin(10) TYPE c,
             wrd(10) TYPE c,
             off(3) TYPE c.

APPEND 'PROGRAM SUBPOOL.'   TO itab.
APPEND 'FORM DYN1.'         TO itab.
APPEND 'WRITE :/ ''I AM A TEMPORARY SUBROUTINE''.' TO itab.
APPEND 'ENDFORM.'           TO itab.

GENERATE SUBROUTINE POOL itab NAME prog MESSAGE msg LINE lin WORD wrd OFFSET off.
*This statement creates a subroutine pool in the main memory area of the running prog
*You pass the source code of the subroutine pool in internal table <itab>.
* The statement returns the name of the generated subroutine pool in field <prog> .
IF sy-subrc <> 0.
WRITE :/ 'ERROR DURING GENERATION OF LINE ', LIN,
             / MSG,
            / 'WORD:', WRD, 'AT OFFSET :', OFF.
ENDIF.
WRITE :/ 'SUBROUTINE POOL NAME=', PROG.
PERFORM dyn1 IN PROGRAM (prog).
_____________________________________________________________________________________
*Generating Persistent Program Programatically
data : itab TYPE TABLE OF string.
CONSTANTS : rep(40) VALUE 'ZDYN_PRO'.
APPEND 'PROGRAM ZDYN_PRO.' TO ITAB.
APPEND 'WRITE :/ '' I AM DYNAMICALLY CREATED ''. ' TO ITAB.
INSERT REPORT REP FROM ITAB.
*above transfers the new executable pgm (ZDYN_PRO)into the program library
SUBMIT (REP) AND RETURN.
____________________________________________________________________________________ 

Creating DDIC Structure Dynamically Using FM

***CREATING A DDIC STRUCTURE DYNAMICALLY USING FUNCTION MODULES ***
**PGM CREATES A DDIC STRUCTURE ZSCARR CONTAINING ALL FIELDS OF SCARR TABLE**
DATA : lt TYPE TABLE OF dd03p,
       ls TYPE dd02v.
FIELD-SYMBOLS : <fs> LIKE LINE OF lt.

CALL FUNCTION 'DDIF_TABL_GET'
  EXPORTING
    name      = 'SCARR'
  IMPORTING
    dd02v_wa  = ls
  TABLES
    dd03p_tab = lt.
ls-tabclass = 'INTTAB' .
ls-tabname  = 'ZSCARR' .
ls-as4user  = sy-uname .
ls-as4time  = sy-uzeit .
ls-as4date  = sy-datum .
ls-applclass = '' .
ls-authclass = '' .
LOOP AT lt ASSIGNING <fs>.
  <fs>-tabname = 'ZSCARR'.
ENDLOOP.
CALL FUNCTION 'DDIF_TABL_PUT'
  EXPORTING
    name           = 'ZSCARR'
   dd02v_wa        = ls
 TABLES
   dd03p_tab       = lt.
IF sy-subrc = 0.
  MESSAGE 'STRUCTURE CREATED ' TYPE 'I'.
ENDIF.
CALL FUNCTION 'DDIF_TABL_ACTIVATE'
  EXPORTING
    name = 'ZSCARR'.
IF sy-subrc = 0.
  MESSAGE 'STRUCTURE ACTIVATED' TYPE 'I'.
ENDIF.

ABAP System Variables

1. SY-CPAGE - Holds Current Page Number

2. SY-CPROG - Contains Program Name

3. SY-CUCOL - Cursor Position ( Column)

4. SY-CUROW - Cursor Position (Line)

5. SY-DATLO  -  Local Date for User

6. SY-DATUM  - System Date

7. SY-DATUD - Global Date Related To UTC ( GMT )

8. SY-DBCNT - Number of entries read by DB Operation

9. SY-DBNAM- Logical DB for ABAP/4 Program

10. SY-DBSYS -  System DB System

11. SY-DYNNR- Number of Current Screen

12. SY-INDEX -  Number Of Loop passes

13. SY-LANGU- SAP Log on Language Key

14. SY-LILLI  - Number Of Current List Line

15. SY-LINCT - Number Of List Lines

16. SY-LINNO - Current Line for List Creation

17. SY-LINSZ - Line Size of List

18. SY-LISEL - Selected Line For Interactive List

19. SY-LSIND - Number Of Secondary List

20. SY-MANDT - Client Number For SAP Log On

21.SY-MSGID  - Message ID

22. SY-MSGTY - Message Type

23. SY-MSGNO -  Message Number

24. SY-MSGV1 - Message Variable1

25. SY-MSGV2 - Message Variable2

26. SY-MSGV3 - Message Variable3

27. SY-MSGV4 - Message Variable4

28. SY-OPSYS - Operating System

29. SY-PAART -  Print Format

30. SY-PAGCT - Page Size of List in Report Program

31. SY-PAGNO - Current Page in the List

33. SY-PDEST - Print Output Device

34. SY-PFKEY - Run time Current F key Status

35. SY-REPID - Report Name in ABAP

36. SY-SAPRL -  SAP Release

37. SY-SUBRC - Return Value after specific ABAP Statement

38. SY-SYSID - SAP system ID

39. SY-TABIX  -  Current line of Internal Table

40. SY-TCODE - Current Transaction Code

41. SY-TIMLO - Local Time Of User

42. SY-TITLE  - Title of ABAP Program

43. SY-TMAXL - Maximum entries in a Internal Table

44. SY-TNAME  - Name Of Internal Table after first Access

45. SY-UCOMM -Interact : Command field Function entry / Function code

46. SY-ULINE  - Underline

47. SY-UNAME - Session : SAP user from Log On

48. SY-UZEIT  - System Time

49. SY-VLINE  - Vertical Bar