关于SQL数据库的一个问题

[supercsharp]

create table StudentInfo
(
StudentID char(7) not null primary key,
StudentName char(10) not null unique,
StudentAge int null,
StudentBirthday varchar(20) not null,
StudentAddress varchar(50) null,
StudentMobilePhone varchar(11) null,
StudentSex char(2) not null,
StudentPhone char(8) null,
StudentClass char(20) null
)
我设了StudentID为主键,StudentName为Unique约束,然后在下面的表中想定义两个外键约束,使这两个外键约束和StudentID,StudentName有相同的值:
create table StudentGrade
(
StudentID char(7) not null references StudentInfo(StudentID)on update cascade on delete cascade,
StudentName char(10) not null references StudentInfo(StudentID)on update cascade on delete cascade,
MathGrade int not null check(MathGrade >0 and MathGrade<100),
ChineseGrade int not null check(ChineseGrade>0 and ChineseGrade<100),
EnglishGrade int not null check(EnglishGrade>0 and EnglishGrade<100),
TotleGrade int null ,
EvenGrade int null ,
ClassRate int null check (ClassRate>0),
GradeRate int null check (GradeRate>0)
)
我想使这个表中的StudentID,StudentName和上面表中的StudentID,StudentName相对应,应该怎么实现?