Question

创建触发器：当删除学生表S中的一条学生记录时，自动删除选修表SC中该学生的成绩记录

Answer 1

MSSQL:

首先你的学号在sc的外键必须是 on delete cascade

alter table sc

add constraint fk_test foreign key (学号) references s(学号) on delete cascade

create trigger test on s

after delete

as

begin

delete from sc where 学号 in (select 学号 from deleted)

end

Oracle：

create or replace trigger test

after delete on s

for each row

begin

delete from sc where 学号=:old.学号;

end;

扩展资料：

SQL语法

DELIMITER |

CREATE TRIGGER `<databaseName>`.`<triggerName>`

< [ BEFORE | AFTER ] > < [ INSERT | UPDATE | DELETE ] >

ON [dbo]<tableName> //dbo代表该表的所有者

FOR EACH ROW

BEGIN

--do something

END |

参考资料来源：百度百科-触发器

Answer 2

MSSQL:
首先你的学号在sc的外键必须是 on delete cascade
alter table sc
add constraint fk_test foreign key (学号) references s(学号) on delete cascade
然后
create trigger test on s
after delete
as
begin
delete from sc where 学号 in (select 学号 from deleted)
end

Oracle：
create or replace trigger test
after delete on s
for each row
begin
delete from sc where 学号=:old.学号;
end;

Answer 3

MySQL
DELIMITER $$
CREATE TRIGGER trg_s
BEFORE
DELETE
ON s #触发地点
FOR EACH ROW
BEGIN
DELETE FROM sc WHERE 学号 = OLD.学号;
END $$
DELIMITER;