php+Mysqli利用事务处理转账问题实例

<?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();
?>