Leer valores de campos tipo LONG en una tabla

create table valores (
Tabla varchar2(80),
campo varchar2(80),
valor_de_facto varchar2(2000))
/
declare
cursor my_cursor is
select table_name, column_name, data_default
from all_tab_columns
where owner='owner' and data_default is not null;
my_var varchar2(2000);
tabla varchar2(80);
columna varchar2(80);
begin
open my_cursor;
loop
fetch my_cursor into tabla, columna, my_var;
exit when my_cursor%notfound;
my_var := substr(my_var,1,2000);
insert into valores values (tabla, columna, my_var);
end loop;
close my_cursor;
end;
/