MySQL -U防止人为误操作

-U, --safe-updates Only allow UPDATE and DELETE that uses keys.
-U, --i-am-a-dummy Synonym for option --safe-updates, -U.
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

[root@db111 ~]# mysql -uroot -p123 -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 erlianzhang.test;
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

[root@db111 ~]# alias mysql=‘mysql -U‘
[root@db111 ~]# mysql -uroot -p123 -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 erlianzhang.test;
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 erlianzhang.test where Sno=5;
Query OK, 1 row affected (0.02 sec)
mysql> quit
Bye
[root@db111 ~]# echo "alias mysql=‘mysql -U‘" >>/etc/profile
[root@db111 ~]# . /etc/profile
[root@db111 ~]# tail -1 /etc/profile
alias mysql=‘mysql -U‘