mysql-自动增量重置为0,但是不能插入id = 0的值.值> 0不会发生

我偶然发现了一个非常奇怪的行为：

想象一下,我们有一个餐桌顾客：

MariaDB [connections]> describe customers;
+--------------+-------------+------+-----+---------+----------------+
| Field        | Type        | Null | Key | Default | Extra          |
+--------------+-------------+------+-----+---------+----------------+
| customerId   | int(11)     | NO   | PRI | NULL    | auto_increment |
| customerName | varchar(50) | NO   |     | NULL    |                |
+--------------+-------------+------+-----+---------+----------------+
2 rows in set (0.00 sec)

插入几个值：

insert into customers(customerName) values('Foo');
insert into customers(customerName) values('Bar');

然后删除所有内容并重置自动增量：

DELETE FROM customers;
ALTER TABLE customers AUTO_INCREMENT = 0;

现在,插入一个带有customerId = 0的新值：

INSERT INTO customers(customerId,customerName) VALUES(0,'Site owner');

并查看结果：

MariaDB [connections]> select * from customers;
+------------+--------------+
| customerId | customerName |
+------------+--------------+
|          1 | Site owner   |
+------------+--------------+
1 row in set (0.00 sec)

customerId设置为1 !!!!

重复相同的过程,但重置为5并插入5,一切正常：

MariaDB [connections]> delete from customers;
Query OK, 1 row affected (0.00 sec)

MariaDB [connections]> ALTER TABLE customers AUTO_INCREMENT = 5;
Query OK, 0 rows affected (0.00 sec)               
Records: 0  Duplicates: 0  Warnings: 0

MariaDB [connections]> INSERT INTO customers(customerId,customerName) VALUES(5,'Site owner');
Query OK, 1 row affected (0.00 sec)

MariaDB [connections]> select * from customers;
+------------+--------------+
| customerId | customerName |
+------------+--------------+
|          5 | Site owner   |
+------------+--------------+
1 row in set (0.00 sec)

这里发生了什么？如何插入值“ 0”和插入值？ (是的,我以后可以编辑,但由于各种原因,对于我的情况而言,这是不切实际的).

谢谢！

解决方法:

我已经参考了link的答案

您可以使用：

SET [GLOBAL|SESSION] sql_mode='NO_AUTO_VALUE_ON_ZERO'

如此处所述,这将防止MySQL将INSERT / UPDATE ID 0解释为下一个序列ID.这种行为将被限制为NULL.

这就是我认为应用程序中非常糟糕的行为.您必须非常谨慎地确保它的使用一致,尤其是如果您选择以后实施复制时.

标签：sql-insert,mariadb,auto-increment,mysql
来源： https://codeday.me/bug/20191030/1967692.html