防止人为误操作MySQL数据库技巧一例
（本题来自老男孩培训内部学生问题，属于数据库安全技巧）
在若干年前，老男孩亲自遇到一个“命案”，老大登录数据库update一个记录，结果忘了加where，于是悲剧发生了，这使得我对MySQL的增量恢复熟练度远超过其他的知识点，同时也很在意对内的数据库安全，并且每次讲课讲到此处，都会给学生讲这个领导的故事。
1、mysql帮助说明
- [oldboy_c64 ~]# mysql --help|grep dummy
- -U, --i-am-a-dummy Synonym for option --safe-updates, -U.
- i-am-a-dummy FALSE
在mysql命令加上选项-U后，当发出没有WHERE或LIMIT关键字的UPDATE或DELETE时，mysql程序就会拒绝执行
2、指定-U登录测试
- [oldboy_c64 ~]# mysql -uroot -poldboy123 -S /data/3306/mysql.sock -U
- Welcome to the MySQL monitor. Commands end with ; or \g.
- Your MySQL connection id is 14
- Server version: 5.5.32-log MySQL Community Server (GPL)
- Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
- Oracle is a registered trademark of Oracle Corporation and/or its
- affiliates. Other names may be trademarks of their respective
- owners.
- Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
- mysql> delete from oldboy.student;
- ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
- mysql> quit
- Bye
提示：不加条件无法删除，目的达到。
3、做成别名防止老大和DBA误操作
- [oldboy_c64 ~]# alias mysql='mysql -U'
- [oldboy_c64 ~]# mysql -uroot -poldboy123 -S /data/3306/mysql.sock
- Welcome to the MySQL monitor. Commands end with ; or \g.
- Your MySQL connection id is 15
- Server version: 5.5.32-log MySQL Community Server (GPL)
- Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
- mysql> delete from oldboy.student;
- ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
- mysql> delete from oldboy.student where Sno=5;
- Query OK, 1 row affected (0.02 sec)
- mysql> quit
- Bye
- [oldboy_c64 ~]# echo "alias mysql='mysql -U'" >>/etc/profile
- [oldboy_c64 ~]# . /etc/profile
- [oldboy_c64 ~]# tail -1 /etc/profile
- alias mysql='mysql -U'
结论：
在mysql命令加上选项-U后，当发出没有WHERE或LIMIT关键字的UPDATE或DELETE时，mysql程序拒绝执行
