szurubooru/src/Upgrades/Upgrade10.php

<?php
namespace Szurubooru\Upgrades;
use Szurubooru\DatabaseConnection;

class Upgrade10 implements IUpgrade
{
	public function run(DatabaseConnection $databaseConnection)
	{
		$pdo = $databaseConnection->getPDO();
		$driver = $databaseConnection->getDriver();

		$pdo->exec('CREATE TABLE favorites
			(
				id INTEGER PRIMARY KEY ' . ($driver === 'mysql' ? 'AUTO_INCREMENT' : 'AUTOINCREMENT') . ',
				userId INTEGER NOT NULL,
				postId INTEGER NOT NULL,
				time DATETIME NOT NULL,
				UNIQUE (userId, postId)
			)');

		$pdo->exec('
			CREATE TRIGGER favoritesDelete BEFORE DELETE ON favorites
			FOR EACH ROW
			BEGIN
				UPDATE posts SET favCount = favCount - 1 WHERE posts.id = OLD.postId;

				UPDATE posts SET lastFavTime = (
					SELECT MAX(time) FROM favorites
					WHERE favorites.postId = posts.id)
					WHERE posts.id = OLD.postId;
			END');

		$pdo->exec('
			CREATE TRIGGER favoritesInsert AFTER INSERT ON favorites
			FOR EACH ROW
			BEGIN
				UPDATE posts SET favCount = favCount + 1 WHERE posts.id = NEW.postId;

				UPDATE posts SET lastFavTime = (
					SELECT MAX(time) FROM favorites
					WHERE favorites.postId = posts.id)
					WHERE posts.id = NEW.postId;
			END');

		$pdo->exec('
			CREATE TRIGGER favoritesUpdate AFTER UPDATE ON favorites
			FOR EACH ROW
			BEGIN
				UPDATE posts SET favCount = favCount + 1 WHERE posts.id = NEW.postId;
				UPDATE posts SET favCount = favCount - 1 WHERE posts.id = OLD.postId;

				UPDATE posts SET lastFavTime = (
					SELECT MAX(time) FROM favorites
					WHERE favorites.postId = posts.id)
					WHERE posts.id IN (OLD.postId, NEW.postId);
			END');

		$pdo->exec('ALTER TABLE posts ADD COLUMN favCount INTEGER NOT NULL DEFAULT 0');
		$pdo->exec('ALTER TABLE posts ADD COLUMN lastFavTime DATETIME');
	}
}