exec("ALTER TABLE tasks ADD COLUMN owner_ms INT DEFAULT '0'"); $pdo->exec(" CREATE TABLE multiselect ( id SERIAL PRIMARY KEY, external_id VARCHAR(255) DEFAULT '' ) "); $pdo->exec(" CREATE TABLE multiselect_has_users ( group_id INTEGER NOT NULL, user_id INTEGER 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) ) "); } function version_1(PDO $pdo) { $pdo->exec("ALTER TABLE tasks ADD COLUMN owner_gp INT DEFAULT '0'"); }