Read view
It allows to hide all instrument panels
Answer:
Choose internet is the right answer
Answer:
The trigger code is given below
create trigger F1_Del
after delete on Friend
for each row
when exists (select * from Friend
where ID1 = Old.ID2 and ID2 = Old.ID1)
begin
delete from Friend
where (ID1 = Old.ID2 and ID2 = Old.ID1);
end
create trigger F1_Insert
after insert on Friend
for each row
when not exists (select * from Friend
where ID1 = New.ID2 and ID2 = New.ID1)
begin
insert into Friend values (New.ID2, New.ID1);
end
