Import parametes and insert into database table suggestions

Question

experts need suggestions
created a table with 3 fields.
zstable.
field dataelement type length
kunnr  kunnr      char  10       key field
name   dname      char   30      key field
aedat aedat        dats  8
aenam  aenam       char  12
now i am creating a function modlue with two input parameters
1)kunnr
2)name
i want to update this two fields into table zstable.
1. so suggest me the best way to do this.
Delcarations in import options which one of the below is best and why?
name type char30
kunnr type kunnr
or
name like zstable-name
kunnr like zstable-kunnr
or
kunnr type zstable-kunnr
name type zstable-name.
2. inserting into table
the data that we recieve from the import parameters need to be inserted into the zstable.
please suggest me the appropriate statement  waht i need to code for this.
insert kunnr name into zstable.
can i ignore the third field as it is not the key field?
3. before inserting do i need to check whether kunnr and uname is initial ie import parametrs?
4. suppose if i delcared two input parameters  in function module zfuntion say vbeln and posnr.
  and source code
insert vbeln and posnr into zstable.
now i am calling from the program
zreport.
call function 'ZFUNCTION'.
EXPORT
NAME =
KUNNR =
Will the above statement updates the blank records into the table zstable?.

Answer 1

Hi,
1) I think the best is either refer directly to data element or to table field. This is beacuse once any change is made to this data element it will automatically reflect in your parameters. For table fields it is a bit less safier but still correct. Golden rule - always try to refer to DDIC components like data elements.
name type dname
kunnr type kunnr
2) You need to provide all key fields. I recommend to use MODIFY as it would hanlde both INSERT (if yet no such record exists ) and UPDATE (if already exists).
data: wa_zstable type zstable. "declare work area
wa_zstable-kunnr = kunnr.  "pass parameters here
wa_zstable-name = name.
modify zstable from wa_zstable.
3) good practise, for this use
if kunnr is initial and  
   name is initial.
  "modify ...
endif.
"or if parameters are set as OPTIONAL, then use
if kunnr is supplied and
   name is supplied.
endif.
4) No, the statment you want to use
insert vbeln and posnr into zstable.
is only used for FIELD GROUPS, not DB table. Please refer [INSERT|http://help.sap.com/abapdocu/en/ABAPINSERT_DBTAB_SHORTREF.htm] for correct syntax.
You can alternatively use somthing like
UPDATE zstable SET vbeln = ...
                                        posnr = ...
                                 WHERE ...
This will update fields VBELN and PONR for all records fullfilling WHERE condition. These however musn't be key fields, only non-key fields can be udpated.
Regards
Marcin