这篇文章给大家分享的是有关Mysq中l建立测试父表、子表及测试用例的示例的内容。小编觉得挺实用的,因此分享给大家做个参考,一起跟随小编过来看看吧。
select version();
5.7.22
drop table if exists Models;
CREATE TABLE Models
(
ModelID SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
Name VARCHAR(40) NOT NULL,
PRIMARY KEY (ModelID)
);
drop table if exists Orders;
CREATE TABLE Orders
(
ID SMALLINT UNSIGNED NOT NULL PRIMARY KEY,
ModelID SMALLINT UNSIGNED NOT NULL,
Description VARCHAR(40),
FOREIGN KEY (ModelID) REFERENCES Models (ModelID)
ON DELETE cascade
);
insert into Orders(Id,ModelID,Description) values (1,1,'a');
结果:执行失败
异常:[2018-07-31 11:08:01] 23000 Cannot add or update a child row: a foreign key constraint fails (bov
.Orders
, CONSTRAINT Orders_ibfk_1
FOREIGN KEY (ModelID
) REFERENCES Models
(ModelID
) ON DELETE CASCADE)
原因:通不过on delete cascade 的外键约束检查
insert into Models(ModelID,Name) values (1,'a');
insert into Orders(Id,ModelID,Description) values (1,1,'a');
结果:执行成功
select * from Models;
1 a
select * from Orders;
1 1 a
delete from Orders where id = 1;
结果:执行成功
select * from Models;
1 a
select * from Orders;
为空
delete from Models where ModelID = 1;
结果:执行成功
select * from Models;
为空
select * from Orders;
为空
update Orders set ModelID = 3 where ID =1;
结果:执行失败
异常:[2018-07-31 12:33:02] 23000 Cannot add or update a child row: a foreign key constraint fails (bov
.Orders
, CONSTRAINT Orders_ibfk_1
FOREIGN KEY (ModelID
) REFERENCES Models
(ModelID
) ON DELETE CASCADE)
原因:通不过on delete cascade 的外键约束检查
update Models set ModelID = 2 where ModelID =1;
结果:执行失败
异常:[2018-07-31 12:34:24] 23000 Cannot delete or update a parent row: a foreign key constraint fails (bov
.Orders
, CONSTRAINT Orders_ibfk_1
FOREIGN KEY (ModelID
) REFERENCES Models
(ModelID
) ON DELETE CASCADE)
原因:通不过on delete cascade 的外键约束检查
update Orders set Description = 'b' where ID =1;
结果:执行成功
select * from Orders;
1 1 b
update Models set Name = 'c' where ModelID =1;
结果:执行成功
select * from Models;
1 c
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