exec("ALTER TABLE `tasks` ADD COLUMN `owner_ms` INT DEFAULT '0'"); $pdo->exec(" CREATE TABLE `multiselect` ( id INT NOT NULL AUTO_INCREMENT, external_id VARCHAR(255) DEFAULT '', PRIMARY KEY(id) ) ENGINE=InnoDB CHARSET=utf8 "); $pdo->exec(" CREATE TABLE multiselect_has_users ( group_id INT NOT NULL, user_id INT NOT NULL, FOREIGN KEY(group_id) REFERENCES `multiselect`(id) ON DELETE CASCADE, FOREIGN KEY(user_id) REFERENCES users(id) ON DELETE CASCADE, UNIQUE(group_id, user_id) ) ENGINE=InnoDB CHARSET=utf8 "); } function version_1(PDO $pdo) { $pdo->exec("ALTER TABLE `tasks` ADD COLUMN `owner_gp` INT DEFAULT '0'"); }