Update Routine ABAP question

Question

Hi,
I am updating data between two ODS objects using some update routines. I would like to write the following routine (in pseudo code):
++++++++++++++++++++++++++++++++++++++++++++++++++++
Check if the characteristic i am updating is not null
IF COMM_STRUCTURE-field1 = 'value1'     AND
         COMM_STRUCTURE-field2 = 'value2'.
RESULT COMM_STRUCTURE-field3.
ELSE.
Don't update anything
END IF
+++++++++++++++++++++++++++++++++++++++++++++++++++
My questions:
1. How i tell the routine not to update anything (as specified in the pseudo code)?
2. How i can check that the characteristic i woul like to update is not null?
3. What is the preferred debug method in case i do not use the PSA?
BR,
Xibi

Answer 1

Thanks Siggi for your prompt and helpful answer. There are however some fundamental things which are not fully clear to me (BTW, where i can find some good documentation on ABAP for BW??):
> Hi,
>
> 1. How i tell the routine not to update anything (as
> specified in the pseudo code)?
>
> set the returncode to a value <> 0.
I wrote the following:
returncode = 1.
Consequently the updated failed. Maybe i am doing something wrong but my intention is not to have the whole thing fail, but rather skip the update for some records.
> 2. How i can check that the characteristic i woul
> like to update is not null?
>
> if not comm_structure-<fieldname> is initial.
The problem is that the characteristic i am trying to update is not contained in the source ODS but only in the target one. Will "if not comm_structure-<fieldname> is initial" still work in this case?
>
> 3. What is the preferred debug method in case i do
> not use the PSA?
>
> Without psa, you need to add a endless loop:
> statics: st_flag type c value '0'.
>
> while st_flag = '0'.
> break-point.
> endwhile.
>
>
> Hope this helps!
>
> regards
>
> Siggi