SQL——添加约束的语句

---添加主键约束   
Alter Table stuInfo   
Add Constraint  PK_stuNO primary Key(stuNo)   
---添加唯一约束   
Alter Table stuInfo   
Add Constraint UQ_stuID unique(stuID)   
---添加默认约束   
Alter Table stuInfo   
Add Constraint DF_stuAddress default('地址不详') for stuAddress   
---添加检查约束   
Alter Table stuInfo   
Add Constraint CK_stuAge check(stuAge between 15 and 40)   
---添加外键约束   
Alter Table stuMarks   
Add Constraint FK_stuNo foreign key(stuNo) references stuInfo(stuNo)