今天，一位原公司的同事，打電話來問我說誤操作了資料庫資料，如何恢復。他原本的想法是登入資料庫update一個記錄，結果忘了加where，於是悲劇發生了。今天，我們不講如何恢復誤操作的資料，我們講講如何從源頭上避免這樣的問題，這才是避免類似問題的根本措施。好了。我們直接進入主題：

1、MySQL幫助說明

[[email protected] ~]# mysql --help|grep dummy      
 -U, --i-am-a-dummy Synonym for option --safe-updates, -U.
i-am-a-dummy      FALSE

2、指定-U登入測試

[[email protected] ~]# mysql -uroot -proot -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
 

3、做成別名防止他人和DBA誤操作

[[email protected] ~]# alias mysql='mysql -U'
[[email protected] ~]# 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
[
 
[email protected] ~]# echo "alias mysql='mysql -U'" >>/etc/profile
[[email protected] ~]# . /etc/profile
[[email protected] ~]# tail -1 /etc/profile
alias mysql='mysql -U'

4、結論：

在mysql命令加上選項-U後，當發出沒有WHERE或LIMIT關鍵字的UPDATE或DELETE時，mysql程式拒絕執行