时间:2021-07-01 10:21:17 帮助过:46人阅读
1、mysql帮助说明
# 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
# 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:此处不加条件无法删除,目的达到。
3、做成别名防止DBA误操作
# alias mysql='mysql -U' # 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 # echo "alias mysql='mysql -U'" >>/etc/profile # . /etc/profile # 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