PL/SQL永久注册码参考地址如下：
https://www.cnblogs.com/sjli-blog/p/12018976.html
https://note.youdao.com/ynoteshare1/index.html?id=c2bdd7bf1e1478a2470267f58eada964&type=note
https://www.cnblogs.com/jijm123/p/13393008.html
https://blog.csdn.net/he__xu/article/details/84065874