创建一个表的同时以自己的一个属性做外键该怎么写啊,我这样写为什么有问题
CREATE TABLE Course
(Cno CHAR(4) PRIMARY KEY,
Cname CHAR(40),
Cpno CHAR(4),
Ccredit SMALLINT,
FOREIGN KEY Cpno REFERENCES Course(Cno)
);
CREATE TABLE Course
(Cno CHAR(4) PRIMARY KEY,
Cname CHAR(40),
Cpno CHAR(4),
Ccredit SMALLINT,
FOREIGN KEY Cpno REFERENCES Course(Cno)
);
CREATE TABLE Course(
Cno CHAR(4) PRIMARY KEY,
Cname CHAR(40),
Cpno CHAR(4),
Ccredit SMALLINT
);ALTER TABLE Course ADD CONSTRAINT
FK_Course_Course FOREIGN KEY
(
Cpno
) REFERENCES dbo.Course
(
Cno
)
ON UPDATE NO ACTION
ON DELETE NO ACTION
(Cno CHAR(4) PRIMARY KEY,
Cname CHAR(40),
Cpno CHAR(4) FOREIGN KEY REFERENCES Course(Cno),
Ccredit SMALLINT
);