oracle中，改变表名和字段名的大小写

begin
   for c in (select table_name tn from user_tables where table_name <> lower(table_name)) loop
       begin
          execute immediate 'alter table '||c.tn||' rename to "'||lower(c.tn)||'"';
       exception
          when others then
             dbms_output.put_line(c.tn||'已存在');
       end;
   end loop; 
end;

begin   
  for t in (select table_name tn from user_tables) 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 "'||lower(c.cn)||'"';
             exception
                when others then
                   dbms_output.put_line(t.tn||'.'||c.cn||'已经存在');
             end;
         end loop;
      end;
  end loop; 
end;