SQL> get del
  1  DECLARE
  2  cursor  c1 is select table_name,owner from dba_tables where
  3     owner=upper('&username');
  4   Str varchar2(100);
  5   begin
  6   for mag in c1 loop
  7   exit when c1%notfound;
  8   str:='delete from  '||mag.owner||'.'||mag.table_name;
  9   execute immediate str;
 10   end loop;
 11* end;