sql sever 建表语法问题

Question

CREATE TABLE Ligh_Students
  (lgh_Sno CHAR(5) PRIMARY KEY,
    lgh_Sname CHAR(10) NOT NULL,
    lgh_Semail CHAR(10),
    lgh_Scredit INT CHECK(lgh_Scredit>=0),
    lgh_Sroom CHAR(5))
CREATE TABLE Ligh_Teachers
    ( lgh_Tno CHAR(5) PRIMARY KEY,
      lgh_Tname CHAR(10) NOT NULL,
      lgh_Temail CHAR(10),
      lgh_Tsalary INT)
CREATE TABLE Ligh_Courses
    ( lgh_Cno CHAR(5) PRIMARY KEY,
      lgh_Cname CHAR(10) NOT NULL,
      lgh_Ccredit INT)
CREATE TABLE Ligh_Reports
    ( lgh_Sno CHAR(5),
      lgh_Tno CHAR(5),
      lgh_Cno CHAR(5),
      lgh_Score INT,
      PRIMARY KEY(lgh_Sno,lgh_Tno,lgh_Cno),
      CONSTERAINT  lgh_Students FOREIGN KEY(lgh_Sno) REFERENCES Ligh_Students,
      CONSTERAINT  lgh_Teachers FOREIGN KEY(lgh_Tno) REFERENCES Ligh_Teachers,
      CONSTERAINT  lgh_Coursers FOREIGN KEY(lgh_Cno) REFERENCES Ligh_Courses)

消息 2715，级别 16，状态 6，第 16 行
第 5 个列、参数或变量: 找不到数据类型 lgh_Students。

请问这个错误是什么意思，CONSTERAINT后面的 lgh_Students不是我命名的约束名吗？

Answer 1

加约束的语法有问题 要这样： Alter Table 表名 Add Constraint 约束名 约束类型 具体的约束类型
Alter Table Ligh_Students, Add CONSTERAINT lgh_Students FOREIGN KEY(lgh_Sno)