DELIMITER // 在 MySQL 的触发器中起什么作用？

DELIMITER // 可以用于将语句的分号（;）更改为//。现在您可以在触发器中使用分号编写多个语句。

这是触发器的演示。在此示例中，每当您输入的EmployeeSalary小于1000时，它将默认设置为10000。

首先，让我们创建一个表。创建表的查询如下 -

mysql> create table EmployeeTable -> ( -> EmployeeId int, -> EmployeeName varchar(100), -> EmployeeSalary float -> ); Query OK, 0 rows affected (0.76 sec)登录后复制

mysql> delimiter // mysql> create trigger CheckSalary before insert on EmployeeTable -> for each row if new.EmployeeSalary new.EmployeeSalary=10000; -> end if; -> // Query OK, 0 rows affected (0.40 sec) mysql> delimiter ;登录后复制

插入记录的查询如下 -

mysql> insert into EmployeeTable values(1,'Carol',500); Query OK, 1 row affected (0.25 sec)登录后复制

mysql> select *from EmployeeTable;登录后复制登录后复制

+------------+--------------+----------------+ | EmployeeId | EmployeeName | EmployeeSalary | +------------+--------------+----------------+ | 1 | Carol | 10000 | +------------+--------------+----------------+ 1 row in set (0.00 sec)登录后复制

mysql> truncate table EmployeeTable; Query OK, 0 rows affected (1.44 sec)登录后复制

mysql> insert into EmployeeTable values(2,'Bob',1000); Query OK, 1 row affected (0.14 sec) mysql> insert into EmployeeTable values(3,'Carol',2500); Query OK, 1 row affected (0.19 sec)登录后复制

mysql> select *from EmployeeTable;登录后复制登录后复制

+------------+--------------+----------------+ | EmployeeId | EmployeeName | EmployeeSalary | +------------+--------------+----------------+ | 2 | Bob | 1000 | | 3 | Carol | 2500 | +------------+--------------+----------------+ 2 rows in set (0.00 sec)登录后复制

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