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CREATe TABLE Student
(Sno CHAR(9) PRIMARY KEY,
Sname char(40) unique,
Ssex char(2),
Sdept char(15),
Sage INT
)
CREATe TABLE Course
(Cno char(4) primary key,
Cname char(40),
Cpno char(4),
Ccredit smallint,
foreign key (Cpno) references Course(Cno)
/*表级完整性约束条件,Cpno是外码,被参照表是Course,被参照列是Cno*/
)
CREATe TABLE SC
(Sno char(9),
Cno char(4),
Grade smallint,
primary key (Sno,Cno),
foreign key (Sno) references Student(Sno),
foreign key (Cno) references Course(Cno)
)
go
drop table SC,Course,Student