mysql insert 主键冲突_insert 时防止出现主键冲突错误的方法
最近幾天,產品上線比較多,從內網測試庫導出表的部分內容到線上也就比平時頻繁多了,這時候可能會出現主鍵沖突:
Error Code : 1062
Duplicate entry '1' for key 'PRIMARY'
總結下,三種解決方案來避免出錯
1.insert ignore into
遇主鍵沖突,保持原紀錄
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)
可見 insert ignore
into當遇到主鍵沖突時,不跟改原紀錄,也不報錯
2:REPLACE into
遇主鍵沖突,替換原紀錄,即
先刪除原紀錄,后insert 新紀錄
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 ... ON DUPLICATE KEY UPDATE
其實這個是原本需要執行3條SQL語句(SELECT,INSERT,UPDATE),縮減為1條語句即可完成。
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)
上面語句偽代碼表示即為
if (select * from device where devid=1)
{ update device set status ='drain' where devid=1
}else {insert into device values (1,'readonly','yang')}
很明顯,devid=1
是有的,這樣就執行update操作
mysql> select * from device ;
+-------+--------+-----------+
| devid | status | spec_char |
+-------+--------+-----------+
|
1 | drain? | yangting? |
|
2 | dead?? |
zhong
|
+-------+--------+-----------+
2 rows in set (0.00 sec)
測試表:
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
總結
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