1 <meta http-equiv="Content-Type" content="text/html";charse="utf-8" /> 2 <?php 3 4 /* 将一系列的更新操作放到beginTransaction()和commit()函数中调用，并通过try块执行，就可以保证在更改之前完成，其他人无法看到 */ 5 $dsn = 'mysql:dbname=test;host=localhost'; 6 $username = 'root'; 7 $password = ''; 8 $opt = array(PDO::ATTR_PERSISTENT => true); 9 10 //持续连接数据库 11 try{ 12 $dbh = new PDO($dsn,$username,$password,$opt); 13 }catch(PDOException $e){ 14 echo '数据库连接失败'.$e -> getMessage(); 15 } 16 17 $dbh -> setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);//设置PDO异常处理模式 18 $dbh -> setAttribute(PDO::ATTR_AUTOCOMMIT,0);//关闭自动提交 19 20 try{ 21 $price = 80; 22 $dbh -> beginTransaction();//开始事备 23 24 $affected_row = $dbh -> exec("update account set cash = cash-{$price} where name='userA'"); 25 if($affected_row > 0){ 26 echo "userA成功转出{$price}元人民币<br>"; 27 }else{ 28 throw new PDOException('usrA转出失败'); 29 } 30 31 $affected_row = $dbh -> exec("update account set cash = cash + {$price} where name='userB'"); 32 if($affected_row > 0){ 33 echo "userB成功转入{$price}元人民币<br>"; 34 }else{ 35 throw new PDOException('usrB转入成功'); 36 } 37 38 echo '交易成功'; 39 $dbh -> commit();//如果执行到此处说明两次语句执行成功，整个事务成功 40 41 }catch(PDOException $e){ 42 echo "交易失败".$e -> getMessage(); 43 $dbh -> rollback();//如果事务执行失败，回滚事务 44 } 45 46 $dbh -> setAttribute(PDO::ATTR_AUTOCOMMIT,1);//重新打开自动提交