要不要冗余字段

drop database if exists test;
create database test;
use test;
drop table if exists user;
CREATE TABLE user (
    id INT AUTO_INCREMENT PRIMARY KEY,
    postCount INT,
    topicCount INT
);

drop table if exists topic;
CREATE TABLE topic (
    id INT AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(10),
    userId INT,
    postCount int ,
    foreign key(userId)references user(id) on delete cascade
);

drop table if exists post;
CREATE TABLE post (
    id INT AUTO_INCREMENT PRIMARY KEY,
    content VARCHAR(10),
    topicId INT,
    userId int ,
    foreign key(topicId)references topic(id) on delete cascade,
    foreign key(userId)references user(id) on delete cascade
);

delimiter ;;
create trigger ai_topic after insert on topic  for each row
begin
    update user set topicCount=topicCount+1 where user.id=new.userId;
end;;
create trigger ad_topic after delete on topic for each row 
begin
    update user set topicCOunt=topicCount-1 where user.id=old.userId;
    delete from post where topicId=old.id;
end;;
create trigger ai_post after insert on post for each row
begin
    update user set postCOunt=postCount+1 where user.id=new.userId;
    update topic set postCount=postCOunt+1 where topic.id=new.topicId;
end;;
create trigger ad_post after delete on post for each row 
begin
    update user set postCount=postCount-1 where user.id=old.userId;
    update topic set postCOunt=postCOunt-1 where topic.id=old.topicId;
end;;
delimiter ;