Да, трябва да създадете after insert trigger
за това
delimiter //
create trigger total_votes_count after insert on votes
for each row
begin
if (new.value == 1) then
update posts set total_votes = total_votes+1
where id = new.id_post;
elseif (new.value == -1) then
update posts set total_votes = total_votes-1
where id = new.id_post;
end if;
end;//
delimiter //
За обработка на актуализацията всичко остава същото, само че имате нужда от друг тригер нещо като
delimiter //
create trigger total_votes_count_upd after update on votes
for each row
begin
if (new.value == 1) then
update posts set total_votes = total_votes+1
where id = new.id_post;
elseif (new.value == -1) then
update posts set total_votes = total_votes-1
where id = new.id_post;
end if;
end;//
delimiter //
Тъй като имате 2 таблици за публикации, ще трябва да ги използвате в условието if
delimiter //
create trigger total_votes_count after insert on votes
for each row
begin
if (new.value == 1) then
if (new.table_name == 'post_A') then
update posts_A set total_votes = total_votes+1
where id = new.id_post;
else
update posts_B set total_votes = total_votes+1
where id = new.id_post;
end if;
elseif (new.value == -1) then
if (new.table_name == 'post_A') then
update posts_A set total_votes = total_votes-1
where id = new.id_post;
else
update posts_B set total_votes = total_votes-1
where id = new.id_post;
end if ;
end if;
end;//
delimiter //
Направете същото за тригера за актуализиране.