MySQL 如何将AUTO_INCREMENT应用于列?
AUTO_INCREMENT表示该列将自动获取值。为了说明这一点,我们创建了一个名为“employees”的表,如下所示。
mysql> Show Create Table employees\G
*************************** 1. row ***************************
Table: employees
Create Table:CREATE TABLE`employees`(
`Id` int(11)NOT NULL AUTO_INCREMENT,
`Name` varchar(35)DEFAULT NULL,
PRIMARY KEY(`Id`)
)ENGINE = InnoDB DEFAULT CHARSET = latin1
1 row in set (0.00 sec)
通过以上结果集,我们可以看到id列被赋予了自动递增选项。现在,当我们在Name字段中插入值时,id字段将自动获取值。
mysql> Insert Into employees(Name) Values('Ram');
Query OK,1 row affected(0.09 sec)
mysql> Insert Into employees(Name) Values('Shyam');
Query OK,1 row affected(0.03 sec)
mysql> Insert Into employees(Name) Values('Mohan');
Query OK,1 row affected(0.04 sec)
mysql> Insert Into employees(Name) Values('Sohan');
Query OK,1 row affected(0.04 sec)
mysql> Select * from employees;
+----+-------+
| Id | Name |
+----+-------+
| 1 | Ram |
| 2 | Shyam |
| 3 | Mohan |
| 4 | Sohan |
+----+-------+
4 rows in set (0.00 sec)
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