Sql创建约束

add constraint pk_studentno primary key(StudentNo) //主键
add constraint fk_student_grade_gradeid foreign key(gradeid) references table2(gradeid)
add constraint uq_studentname unique(StudentName) //唯一
add constraint df_address default(N'未填写') for address //默认值
add constraint ck_Gender check (gender=0 or gender=1) //检查
add constraint ck_phone check (phone is not null) //检查