create trigger AddCount before insert on score 
for each row 
update student set Scount = Scount + 1 where Sno in (select Sno from score);

create table Student(
Sno char(3) not null primary key,
Sname char(8) not null,
Scount int null);
 
create table Score(
Sno Char(3) not null,
foreign key (Sno) references student(Sno) on update cascade,
Cno char(5) not null,
Degree decimal(4,1) null);
 
insert student(Sno, Sname, Scount)
values
('108', 'Tom', 40),
('105', 'John', 30),
('107', 'Mary', 23),
('101', 'Jake', 15),
('109', 'Lily', 10),
('103', 'James', 21);

insert score(Sno, Cno, Degree)
values
('103', '3-245', 86),
('105', '3-245', 75),
('109', '3-245', 68),
('103', '3-105', 92),
('105', '3-105', 88),
('109', '3-105', 76),
('101', '3-105', 64),
('107', '3-105', 91),
('107', '6-166', 79),
('108', '6-166', 81);