MySQL FOREIGN KEY 约束报错
本文介绍了MySQL FOREIGN KEY 约束报错的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
问 题
Create table Student
(
Sno varchar(7) primary key,
Sname varchar(10) not null,
Ssex char (2) check(Ssex=‘男’or Ssex=’女’),
Sage int check(Sage between 15 and 45),
Sdept varchar(20) default ‘计算机系’
);
Create table course
(
Cno varchar(10) primary key,
Cname varchar(20) not null,
Ccredit int check(Sctedit>0),
Semester int check(Semester>0),
Period int check(Period>0)
);
Create table SC
(
Sno varchar(7) foreign key references student(Sno),
Cno varchar(10) foreign key references course(Cno),
Grade int check(Grade between 0 and 100),
Primary key (Sno,Cno)
);
前两个可以成功的建表,但是第三个建表报错:
更改第三个:
Create table SC
(
Sno varchar(7),
Cno varchar(10),
Grade int check(Grade between 0 and 100),
foreign key (Sno) references student(Sno),
foreign key (Cno) references course(Cno),
Primary key (Sno,Cno),
);
还是报错:
求解答,谢谢大佬!
解决方案
创建外键的写法错误吧,
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