添加外键约束,主表student的字段sno与从表score的字段sno关联,下列T-SQL语句正确的是()。
A.
alter table student add constraint FK_Sno foreign key(sno) references score(sno)
B.
alter table score add constraint FK_Sno foreign key(sno) references student(sno)
C.
alter table score add constraint PK_Sno primary key(sno) references student(sno)
D.
alter table student add constraint PK_Sno primary key(sno) references score(sno)