php+Mysqli利用事务处理转账问题的方法

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<?php

header("Content-type:text/html; charset=utf-8");

$mysqli = new mysqli("localhost", "root", "064319", "php");

$mysqli->set_charset("utf8");

if($mysqli->connect_errno) {

die('数据库连接失败'.$mysqli->connect_error);

}

$mysqli->autocommit(false); //自动提交模式设为false

$flag = true; //事务是否成功执行的标志

$query = "update account set balance=balance-1000 where id=3";

$result = $mysqli->query($query);

$affected_count = $mysqli->affected_rows;

if(!result || $affected_count == 0) { //失败

$flag = false;

}

$query = "update account set balance=balance+1000 where id=2";

$result = $mysqli->query($query);

$affected_count = $mysqli->affected_rows;

if(!$result || $affected_count == 0) {

$flag = false;

}

if($flag) {

$mysqli->commit();

echo '转账成功';

} else {

$mysqli->rollback();

echo '转账失败';

}

$mysqli->autocommit(true); //重新设置事务为自动提交

$mysqli->close();

?>

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<?php

try{

$pdo=new PDO("mysql:host=localhost;dbname=psp","root","");

$pdo->exec("set names utf8");

$pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);//设置异常处理模式

$pdo->setAttribute(PDO::ATTR_AUTOCOMMIT,0);//关闭自动提交

}catch(PDOException $e){

echo "数据库连接失败";

exit;

}

try{

$age=10;

$pdo->beginTransaction();//开始事务

$affected_rows1=$pdo->exec("update kfry set k_age=k_age+{$age} where k_name='user1'");

$affected_rows2=$pdo->exec("update kfry set k_age=k_age-{$age} where k_name='user2'");//随意更改使之执行成功或失败

/* if($affected_rows1&&$affected_rows2)

{

$pdo->commit();

echo "操作成功";

}else{

$pdo->rollback();

} */

if(!$affected_rows1)

throw new PDOException("加入错误");

if(!$affected_rows2)

throw new PDOException("减少错误");

echo "操作成功";

$pdo->commit();//如果执行到此处前面两个更新sql语句执行成功，整个事务执行成功

}catch(PDOException $e){

echo "操作失败：".$e->getMessage();

$pdo->rollback();//执行事务中的语句出了问题，整个事务全部撤销

}

$pdo->setAttribute(PDO::ATTR_AUTOCOMMIT,1);

//测试是否成功

echo "\n操作结果为:\n";

$sql="select * from kfry";

$result=$pdo->query($sql);

foreach($result as $v)

{

echo $v['k_name']." ".$v['k_age']."\n";

}

?>