Tornado中database模块被取消的替代方法

准备用用tornado重写本站，但发现import tornado.database时出错。
代码如下:
[root@lee ~]# python
Python 2.7.4 (default, Apr 11 2013, 17:08:33)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import tornado.web
>>> import tornado.database
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named database
>>>
网上不少教程明明写的是这个模块，怎么会提示找不到这个模块呢？难道我没有安装MySQLdb的原因？
代码如下:
[root@lee tornado]# python
Python 2.7.4 (default, Apr 11 2013, 17:08:33)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import MySQLdb
>>>
MySQLdb模块已经装好了，看来不是MySQLdb模块引起的。我又重装了一次tornado，结果还是没有database模块。

Python的模块就是一个py文件，我倒tornado目录去看了看，果然没有database.py这个模块：
代码如下:
[root@lee ~]# find /usr -name tornado
/usr/lib/python2.6/site-packages/tornado-3.0.1-py2.6.egg/tornado
/usr/local/lib/python2.7/site-packages/tornado-3.0.1-py2.7.egg/tornado
/usr/local/lib/python2.7/site-packages/tornado
[root@lee ~]# cd /usr/local/lib/python2.7/site-packages/tornado
[root@lee tornado]# ls
auth.py              escape.pyc      __init__.pyc  netutil.pyc            tcpserver.py   web.pyc
auth.pyc             gen.py          ioloop.py     options.py             tcpserver.pyc  websocket.py
autoreload.py        gen.pyc         ioloop.pyc    options.pyc            template.py    websocket.pyc
autoreload.pyc       httpclient.py   iostream.py   platform               template.pyc   wsgi.py
ca-certificates.crt  httpclient.pyc  iostream.pyc  process.py             test           wsgi.pyc
concurrent.py        httpserver.py   locale.py     process.pyc            testing.py