http://hudeyong926.iteye.com/blog/1484367
http://blog.csdn.net/jake451/article/details/6117272
http://www.verydemo.com/demo_c116_i6841.html
http://lxy.me/the-the-yii-mysql-database-and-read-write-separation.html
http://blog.csdn.net/xinqingch/article/details/8186745
