declare

i integer;

v_rowid rowid;

var rowid;

cursor cur is

select t.row1

from tmp t;

cursor data is

select c.test

from countries c

where rowid = v_rowid;

begin

for rec in cur loop

v_rowid := rec.row1;

update countries c

set c.test = null

where rowid = v_rowid;

end loop;

execute immediate 'commit';

end;