时间:2021-07-01 10:21:17 帮助过:26人阅读
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
相关文章:
mysql数据库索引的建立以及性能测试
mysql 高性能压力测试(总结了好久)
相关视频:
数据结构探险之线性表篇
以上就是Mysq中l建立测试父表、子表及测试用例归纳总结的详细内容,更多请关注Gxl网其它相关文章!