COMPLEX LUW PROCESSING IN ABAP

COMPLEX LUW PROCESSING:


In an ABAP program, there are two ways of executing another program synchronously:
Terminate the current program and start the other program (SUBMIT , LEAVE
TO TRANSACTION )
Call the other program without terminating the other program. The calling program is
Interrupted, and the system returns to it when the program that it has called is finished (CALL
TRANSACTION, SUBMIT AND RETURN, CALL FUNCTION).

You can only use SUBMIT and SUBMIT AND RETURN to start executable programs (program type 'Executable program', formerly program type '1').

You use LEAVE TO TRANSACTION and CALL TRANSACTION to start programs that have a transaction code.

You use CALL FUNCTION to execute a function module.

The executed commands differ with regard to the visibility of program data in the calling program and the called program, and in their behavior with regard to LUW processing.

With the SUBMIT statement, you start programs that are directly executable programs.

The addition VIA SELECTION-SCREEN is used to send the selection screen of the program (if the program has a standard selection screen).

To return to the calling program after the program has finished, use the addition AND RETURN.

Calling an executable program allows you to use a logical database to read data.


You can execute ABAP programs with a transaction code using the statement CALL TRANSACTION . When the program that you called has terminated, the system continues processing the calling program.

If the transaction that you call in the CALL TRANSACTION statement uses update techniques; you can determine which technique it should use (synchronous or asynchronous) using the FUNCTION parameter in the call.

To exit an ABAP program, use the LEAVE PROGRAM statement. If you use this statement in a program that you have called using CALL TRANSACTION or SUBMIT AND RETURN, the system returns to the calling program. Otherwise, the system returns to the application menu from which you started the program.

To initiate a transaction with the transaction code , use the LEAVE TO TRANSACTION statement. This does not allow you to return to where the transaction was called from.
This statement has the same effect as entering /n in the command field.

For further information, see the keyword documentation in the ABAP Editor for CALL and LEAVE.

You can encapsulate dialogs in reusable function modules.

If you call up a screen within a function module, this screen belongs to the program of function group SAPL of the function module.