1.将表格名转成class名
classify
"book_comments".classify => "BookComment"
2.class名转成table_name(和上面的相反)
tableize
"BookComment".tableize => "book_comments"
3.将class名转成class
constantize
"BookComment".constantize => BookComment
4.string复数化(可用于生成table_name)
pluralize
"bookcomment".pluralize => "bookcomments"
5.string单数化
singularize
"bookcomments".singularize => "bookcomment"
原文：http://www.cnblogs.com/wangyuyu/p/4210932.html