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使用"insert into"语句进行数据库操作时可能遇到主键冲突，用户需要根据应用场景进行忽略或者覆盖等操作。总结下，有三种解决方案来避免出错。
1. insert ignore into遇主键冲突，保持原纪录，忽略新插入的记录。mysql> select * from device ;+-------+--------+-------------+| devid | status | spec_char |+-------+--------+-------------+| 1 | dead | zhonghuaren | | 2 | dead | zhong | +-------+--------+-------------+2 rows in set (0.00 sec)mysql> insert into device values (1,'alive','yangting');
ERROR 1062 (23000): Duplicate entry '1' for key 'PRIMARY'mysql> insert ignore into device values (1,'alive','yangting');
Query OK, 0 rows affected (0.00 sec)mysql> select * from device ;
+-------+--------+-------------+| devid | status | spec_char |+-------+--------+-------------+| 1 | dead | zhonghuaren | | 2 | dead | zhong | +-------+--------+-------------+2 rows in set (0.00 sec)可见 insert ignore into当遇到主键冲突时，不更改原纪录，也不报错2. replace into遇主键冲突，替换原纪录，即先删除原纪录，后insert新纪录
mysql> replace into device values (1,'alive','yangting');
Query OK, 2 rows affected (0.00 sec)mysql> select * from device ;
+-------+--------+-----------+| devid | status | spec_char |+-------+--------+-----------+| 1 | alive | yangting | | 2 | dead | zhong | +-------+--------+-----------+2 rows in set (0.00 sec) 3. insert into ... ON DUPLICATE KEY UPDATE其实这个是原本需要执行3条SQL语句（SELECT,INSERT,UPDATE），缩减为1条语句即可完成。即IF (SELECT * FROM where 存在) { UPDATE SET WHERE ;} else { INSERT INTO;}如：mysql> insert into device values (1,'readonly','yang') ON DUPLICATE KEY UPDATE status ='drain';Query OK, 2 rows affected (0.00 sec)上面语句伪代码表示即为
if (select * from device where devid=1) { update device set status ='drain' where devid=1 } else { insert into device values (1,'readonly','yang')}很明显，devid=1 是有的，这样就执行update操作mysql> select * from device ;+-------+--------+-----------+| devid | status | spec_char |+-------+--------+-----------+| 1 | drain | yangting | | 2 | dead | zhong | +-------+--------+-----------+2 rows in set (0.00 sec)测试表：
CREATE TABLE `device` (`devid` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,`status` enum('alive','dead','down','readonly','drain') DEFAULT NULL,`spec_char` varchar(11) DEFAULT '0',PRIMARY KEY (`devid`)) ENGINE=InnoDB