Question

服务器: 消息 1767，级别 16，状态 1，行 1 外键 'FK__SC__Sno__47DBAE45' 引用了无效的表 'Student'。

use JW_System
go
CREATE TABLE SC
(Sno CHAR(10),
Cno CHAR(10),
Grade SMALLINT CHECK(Grade>=0 AND Grade<=100),
PRIMARY KEY (Sno, Cno),
FOREIGN KEY (Sno) REFERENCES Student(Sno)
ON DELETE CASCADE /* 当删除Student表中的元组时，级连删除SC表中相应的元组*/
ON UPDATE CASCADE,/*当更新Student表中的Sno时，级连更新SC表中相应的元组*/
FOREIGN KEY (Cno) REFERENCES Course(Cno) /*表级完整性约束条件，Sno是外码*/
on delete no ACTION
ON UPDATE CASCADE /*当更新Course表中的Cno时，级连更新SC表中相应的元组*/
);
CREATE TABLE Teacher
(Tno CHAR(10) PRIMARY KEY,
Tname CHAR(20),
Tsex CHAR(2),
Tjob CHAR(10),
Tsdept CHAR(10),
Ttel BIGINT,
Dno CHAR(10),
FOREIGN KEY (Dno) REFERENCES Sdept(Dno)
);

CREATE TABLE Student
(Sno CHAR(10) PRIMARY KEY,
Sname CHAR(20) UNIQUE,
Ssex CHAR(2),
Sage SMALLINT,
Sdept CHAR(20),
Sbirth CHAR(10),
Class CHAR(10) REFERENCES Class(Cno) /*表级完整性约束条件，Class是外码*/
);
CREATE TABLE Sdept
(Dno CHAR(10) PRIMARY KEY,
Dname CHAR(20) UNIQUE,
Dtel BIGINT
);

CREATE TABLE Course
(Cno CHAR(10) PRIMARY KEY,
Cname CHAR(20) UNIQUE,
Ccredit SMALLINT,
Ctime SMALLINT,
Tno CHAR(10),
Cpeople BIGINT,
FOREIGN KEY (Tno) REFERENCES Teacher(Tno) /*表级完整性约束条件，Tno是外码*/
);

CREATE TABLE Class
(Cno CHAR(10) PRIMARY KEY,
Lcredit BIGINT,
Tno CHAR(10),
Dno CHAR(10),
FOREIGN KEY (Tno) REFERENCES Teacher(Tno), /*表级完整性约束条件，Tno是外码*/
FOREIGN KEY (Dno) REFERENCES Sdept(Dno)); /*表级完整性约束条件，Dno是外码*/

Answer 1

--楼主 你搞错顺序了 既然有那么多外键 那么肯定要先创建主键表
--帮你改了
use JW_System
go
CREATE TABLE Sdept
(Dno CHAR(10) PRIMARY KEY,
Dname CHAR(20) UNIQUE,
Dtel BIGINT
);
CREATE TABLE Teacher
(Tno CHAR(10) PRIMARY KEY,
Tname CHAR(20),
Tsex CHAR(2),
Tjob CHAR(10),
Tsdept CHAR(10),
Ttel BIGINT,
Dno CHAR(10),
FOREIGN KEY (Dno) REFERENCES Sdept(Dno)
);
CREATE TABLE Class
(Cno CHAR(10) PRIMARY KEY,
Lcredit BIGINT,
Tno CHAR(10),
Dno CHAR(10),
FOREIGN KEY (Tno) REFERENCES Teacher(Tno), /*表级完整性约束条件，Tno是外码*/
FOREIGN KEY (Dno) REFERENCES Sdept(Dno)); /*表级完整性约束条件，Dno是外码*/
CREATE TABLE Student
(Sno CHAR(10) PRIMARY KEY,
Sname CHAR(20) UNIQUE,
Ssex CHAR(2),
Sage SMALLINT,
Sdept CHAR(20),
Sbirth CHAR(10),
Class CHAR(10) REFERENCES Class(Cno) /*表级完整性约束条件，Class是外码*/
);
CREATE TABLE Course
(Cno CHAR(10) PRIMARY KEY,
Cname CHAR(20) UNIQUE,
Ccredit SMALLINT,
Ctime SMALLINT,
Tno CHAR(10),
Cpeople BIGINT,
FOREIGN KEY (Tno) REFERENCES Teacher(Tno) /*表级完整性约束条件，Tno是外码*/
);

CREATE TABLE SC
(Sno CHAR(10),
Cno CHAR(10),
Grade SMALLINT CHECK(Grade>=0 AND Grade<=100),
PRIMARY KEY (Sno, Cno),
FOREIGN KEY (Sno) REFERENCES Student(Sno)
ON DELETE CASCADE /* 当删除Student表中的元组时，级连删除SC表中相应的元组*/
ON UPDATE CASCADE,/*当更新Student表中的Sno时，级连更新SC表中相应的元组*/
FOREIGN KEY (Cno) REFERENCES Course(Cno) /*表级完整性约束条件，Sno是外码*/
on delete no ACTION
ON UPDATE CASCADE /*当更新Course表中的Cno时，级连更新SC表中相应的元组*/
);

--如果解决了楼主的问题 请采纳

Answer 2

我就遇到过，解决办法是 重启SQL 但是原因是什么我真不知道，等待大神解答！