Create table C
(Cno int ,
Sbjuct char(20),
Dno CHAR(9),
Ctime Datetime,
sumpeople int,
check ([sumpeople]<=30),
PRIMARY KEY(Cno)
);create table S
(
Sno CHAR(9) primary key,
Sname CHAR(20) not null,
Sage int,
check ([Sage]>=15 and [Sage]<=40),
Cno int ,
CONSTRAINT F_K_S FOREIGN KEY(Cno)REFERENCES C(Cno)
);
(Cno int ,
Sbjuct char(20),
Dno CHAR(9),
Ctime Datetime,
sumpeople int,
check ([sumpeople]<=30),
PRIMARY KEY(Cno)
);create table S
(
Sno CHAR(9) primary key,
Sname CHAR(20) not null,
Sage int,
check ([Sage]>=15 and [Sage]<=40),
Cno int ,
CONSTRAINT F_K_S FOREIGN KEY(Cno)REFERENCES C(Cno)
);
(Cno int ,
Sbjuct char(20),
Dno CHAR(9),
Ctime Datetime,
sumpeople int,
check ([sumpeople]<=30),
PRIMARY KEY(Cno,Dno,Sbjuct)
);
这里primary key就是PRIMARY KEY(Cno,Dno,Sbjuct)这3个啊
这是正确答案Create table D
(Dno char(9) primary key,
Dname char(20)
);Create table C
(Cno int PRIMARY KEY,
Sbjuct char(20),
Dno CHAR(9),
Ctime Datetime,
sumpeople int,
check ([sumpeople]<=30),
FOREIGN KEY(Dno)REFERENCES D(Dno),
);Create table S
(Sno CHAR(9) primary key ,
Sname CHAR(20) not null,
Sage int,
check ([Sage]>=15 and [Sage]<=40),
Cno int,
FOREIGN KEY(Cno)REFERENCES C(Cno)
);