begin
   for t in (select table_name tn from user_tables where table_name <> upper(table_name)) loop
       begin
          for c in (select column_name cn from user_tab_columns where table_name=t.tn) loop
              begin
                 execute immediate 'alter table "'||t.tn||'" rename column "'||c.cn||'" to '||c.cn;
              exception
                 when others then
                    dbms_output.put_line(t.tn||'.'||c.cn||'已經存在');
              end;
          end loop;
      
          execute immediate 'alter table "'||t.tn||'" rename to '||t.tn;
          exception
             when others then
                dbms_output.put_line(t.tn||'已存在');
       end;
   end loop; 
end;