WHEN-BUTTON-PRESSED trigger raise unhendled exception ORA-01407 - oracle

Question

I am new in PL SQL and I am trying to resolve problem with copy-past data from .CVS file to database
I create a small application which will take data from .CVS and past it to database.
I create a method, but after I compile it's writtend Successfully compiled
But when I run form I get error
WHEN-BUTTON-PRESSED trigger raise unhendled exception ORA-01407
Does anyone know what this means since I google it and could not find anything ?
I would be very thankfull
declare
import_file text_io.file_type;
import_file_name varchar2(1000);
import_log_file text_io.file_type;
import_log_file_name varchar2(1000);
vec_importovano number;
brojac number;
brojac_redova number;
linebuf varchar2(5000);
p_rbr varchar2(4);
p_polica varchar2(20);
p_banka varchar2 (20);
p_kontakt varchar2(20);
kraj_fajla number;
begin
import_file_name := :Global.Lokacija_prenosa||:import.naziv_fajla||:Global.Ekstenzija_prenosa;
import_file := text_io.fopen(import_file_name,'r');
--p_rbr := 100000;
delete from zivot_trajni_nalog_ponude where banka is not null;
commit;
kraj_fajla := 0;
while kraj_fajla = 0 loop
begin
text_io.get_line(import_file, linebuf);
if brojac_redova>=2 then
if length(linebuf)>100 then
p_rbr:=substr(linebuf, 1, instr(linebuf,';',1,1)-1);
p_polica:=substr(linebuf, instr(linebuf,';',1,1)+1, instr(linebuf,';',1,2) - instr(linebuf,';',1,1)-1);
p_banka:=substr(linebuf, instr(linebuf,';',1,2)+1, instr(linebuf,';',1,3) - instr(linebuf,';',1,2)-1);
p_kontakt:=substr(linebuf, instr(linebuf,';',1,3)+1, instr(linebuf,';',1,4) - instr(linebuf,';',1,3)-1);
select count(*)
into vec_importovano
from ZIVOT_TRAJNI_NALOG_PONUDE
where broj_police=p_polica and p_rbr=redni_broj;
if vec_importovano=0 then
insert into ZIVOT_TRAJNI_NALOG_PONUDE values(p_rbr, p_polica, p_banka, p_kontakt);
commit;
end if;
end if;
end if;
EXCEPTION WHEN NO_DATA_FOUND THEN kraj_fajla := 1;
end;
end loop;
update zivot_trajni_nalog_ponude set redni_broj = p_rbr;
commit;
text_io.fclose(import_file);
message('Zavrseno prepisivanje fajla');
end;

Answer 1

The error you got (ORA-01407) means that you are trying to update a column (which is set to NOT NULL) with a NULL value. That won't work. For example:
SQL> create table test (id number not null);
Table created.
SQL> insert into test (id) values (100);
1 row created.
SQL> update test set id = null;
update test set id = null
*
ERROR at line 1:
ORA-01407: cannot update ("SCOTT"."TEST"."ID") to NULL
SQL>
The only UPDATE in your code is this:
UPDATE zivot_trajni_nalog_ponude SET redni_broj = p_rbr;
Apparently, p_rbr is NULL, redni_broj won't accept it and you got the error.
What to do? Debug your code and see why p_rbr doesn't have a value. A simple "solution" might be
IF p_rbr IS NOT NULL
THEN
UPDATE zivot_trajni_nalog_ponude
SET redni_broj = p_rbr;
END IF;
Also, although not related to your problem: don't COMMIT within a loop.

Answer 2

ORA-01407 occurs as you are trying to update/Insert a column to NULL
when the column does not accept NULL values.
To find all the "not null" columns in table ZIVOT_TRAJNI_NALOG_PONUDE, Please check the DDL of the table.