create table test_0079 (col_1 number, col_2 number);

create or replace procedure test_0079_post_ins as
begin
  update test_0079
  set col_2 = sign(col_1);
end;
/

create or replace trigger test_0079_ais 
after insert on test_0079
begin
  test_0079_post_ins;
end;
/

insert into test_0079(col_1) select level -5 from dual connect by level <= 10;

select * from test_0079;

     COL_1      COL_2
---------- ----------
        -4         -1
        -3         -1
        -2         -1
        -1         -1
         0          0
         1          1
         2          1
         3          1
         4          1
         5          1

10 rows selected.