MySQL完成差集(Minus)和交集(Intersect)測試申報。本站提示廣大學習愛好者：（MySQL完成差集(Minus)和交集(Intersect)測試申報）文章只能為提供參考，不一定能成為您想要的結果。以下是MySQL完成差集(Minus)和交集(Intersect)測試申報正文
有很多開辟人員在操作MySQL數據庫的時刻都碰到過誤操作的情形，例如更新數據庫的時刻update語句忘卻加上where前提，就會形成極其喜劇的成果。本文就針對避免MySQL數據庫誤操作的辦法做出以下詳解：
1、mysql贊助解釋
# mysql --help|grep dummy -U, --i-am-a-dummy Synonym for option --safe-updates, -U. i-am-a-dummy FALSE
在mysql敕令加上選項-U後，當收回沒有WHERE或LIMIT症結字的UPDATE或DELETE時，mysql法式就會謝絕履行
2、指定-U登錄測試
# 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
提醒：此處不加前提沒法刪除，目標到達。
3、做成別號避免DBA誤操作
# 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'
結論：在mysql敕令加上選項-U後，當收回沒有WHERE或LIMIT症結字的UPDATE或DELETE時，mysql法式謝絕履行
