php PDO事务的简单应用

<?phpheader("content-type:text/html;charset=utf-8");try{$dsn = "mysql:host=localhost;dbname=yii_ceshi";$pdo = new PDO($dsn,'root','root');$pdo -> query("set names utf8");}catch(PDOException $e){exit($e->getMessage());}try{$sql = "SELECT `money` from bank WHERE `name`='张三'";$arr = $pdo->query($sql)->fetch(PDO::FETCH_ASSOC);if ($arr['money']<=100) {exit("对不起！您的余额不足");}else{$pdo->beginTransaction();//开启事务$sql = "UPDATE bank SET `money`=`money`-100 WHERE `name`='张三'";$info = $pdo->exec($sql);if (!$info) {throw new PDOException('对不起，转账失败，转账金额已退还！');}$sql = "UPDATE bank SET `money`=`money`+100 WHERE `name`='李四'";$info = $pdo->exec($sql);if (!$info) {throw new PDOException('对不起，李四未收到转账金额！');}$pdo->commit();  //事务提交，注意这里的提交默认为自动提交exit("转账成功！");}}catch(PDOException $e){$pdo->rollback();  //事务回滚exit($e->getMessage());}