create table student_course
(
sno_sc char(8),
cno_sc char(10),
score tinyint,
primary key(sno_sc,cno_sc),
constraint sno_sc_FK foreign key(sno_sc) references student(sno),
constraint cno_sc_FK foreign key(cno_sc) references course(cno)
);
你试下。。
create table student_course
(
sno char(8) not null,
cno char(10) not null,
score number,
constraint PK_SC primary key (sno, cno)
)