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PDO在提交/回滚前丢失事务

PDO losing Transaction before commit/rollback

本文关键字：失事 事务 提交 PDO | 更新日期: 2023-09-27

我正在尝试使用事务和mysql使用PDO来完成这项工作。我遇到的问题是，在我提交之前，事务就已经中断了。我知道这一点是因为我在连接上回显inTransaction（）函数。

在我看来，这是因为我正在实例化一个PDODatabase类，然后在实际执行任何查询之前做一些其他编码工作，此时我会丢失事务。

实例化我的类

$pdo = new PdoDatabase;
$pdo->beginTransaction();
echo "first ".$pdo->transactionStarted()."<br />";

PdoDatabase类

public function __construct(){
    $dsn = 'mysql:host='.DB_HOST.';dbname='.DB_NAME;
    $options = array(PDO::ATTR_PERSISTENT => TRUE, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION);
    try{
        $this->_connection = new PDO($dsn, DB_USER, BD_PASS, $options);
    } catch (PDOException $e){
        $this->_error = $e->getMessage();
    }
}
public function query($q){
    if($this->_error != ''){
        echo $this->_error;
    } else {
        $this->_stmt = $this->_connection->prepare($q);
    }
}
public function bind($param, $value, $type = null){
    //echo "<br>".$value."<br>";
    if (is_null($type)) {
      switch (true) {
        case is_int($value):
          $type = PDO::PARAM_INT;
          break;
        case is_bool($value):
          $type = PDO::PARAM_BOOL;
          break;
        case is_null($value):
          $type = PDO::PARAM_NULL;
          break;
        default:
          $type = PDO::PARAM_STR;
      }
    }
    $this->_stmt->bindValue($param, $value, $type);
}
public function execute($class = null){
    $object_array = array();
    if($class !== null){
        if($this->_stmt->execute()){
            $this->_stmt->setFetchMode(PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE, $class, null);
            while($row = $this->returnRow()){
                $object_array[] = $class::instantiate($row);
            }
        }
        return $object_array;
    } else {
        return $this->_stmt->execute();
    }
}
public function transactionStarted(){
    return $this->_connection->inTransaction();
}

我是如何使用它（部分）

if(isset($_POST['id']) && $_POST['id'] != ''){
                echo "id exists ".$pdo->transactionStarted()."<br />";
                $bidder->getBidderById($_POST['id']);
                echo "step 1 ".$pdo->transactionStarted()."<br />";
                $bidder = $bidder->getList(0);
                echo "step 2 ".$pdo->transactionStarted()."<br />";
                $old_bidder = clone $bidder;
                echo "step 3 ".$pdo->transactionStarted()."<br />";
                $bidder_phones->getPhones($_POST['id']);
                echo "step 4 ".$pdo->transactionStarted()."<br />";
                $bidder_phones = $bidder_phones->getList();
                echo "step 5 ".$pdo->transactionStarted()."<br />";
                if($_POST['phone'] == ''){
                    // check to see if there are any phone numbers in the database already and delete if there is
                    foreach($bidder_phones as $bp){
                        $q = "delete from bidder_phones where id = :id";
                        $pdo->query($q);
                        $pdo->bind(":id", $bp->getId());
                        $pdo->execute();
                        //$bp->remove();
                    }
                } else {
                    echo "phone to check ".$pdo->transactionStarted()."<br />";
                    $old_phone_numbers = array();
                    $new_phone_numbers = explode(',', $_POST['phone']);
                    foreach($bidder_phones as $bp){
                        // remove any unused phone numbers
                        if(!in_array($bp, $new_phone_numbers)){
                            $q = "delete from bidder_phones where id = :id";
                            $pdo->query($q);
                            $pdo->bind(":id", $bp->getId());
                            $pdo->execute();
                            //$bp->remove();
                        }
                        // push to an array to test the new numbers
                        array_push($old_phone_numbers, $bp->getPhone());
                    }
                    foreach($new_phone_numbers as $phone){
                        // adding new phone numbers
                        if(!in_array($phone, $old_phone_numbers)){
                            $new_phone = new BidderPhone;
                            $new_phone->setPhone($phone);
                            $new_phone->setBidderId($_POST['id']);
                            $pdo->save('BidderPhones', $new_phone);
                            //$new_phone->save();
                        }
                    }
                }

正如您所看到的，我多次回显$pdo->transactionStarted（）。这是一次尝试，看看我什么时候会输掉交易。我希望看到的是我的消息后面跟着一个1，以显示事务仍然处于活动状态。这就是我得到的：

first 1
id exists 1
step 1
step 2
step 3
step 4
step 5
phone to check
in save
before create
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42S02]: Base table or view not found: 1146 Table 'clickbid.bidder_phoneses' doesn't exist' in /var/www/classes/PdoDatabase.php:59 Stack trace: #0 /var/www/classes/PdoDatabase.php(59): PDOStatement->execute() #1 /var/www/classes/PdoDatabase.php(158): PdoDatabase->execute() #2 /var/www/classes/PdoDatabase.php(187): PdoDatabase->getFields('BidderPhones') #3 /var/www/classes/PdoDatabase.php(176): PdoDatabase->create('BidderPhones', Object(BidderPhone), false) #4 /var/www/admin/data/post_data.php(284): PdoDatabase->save('BidderPhones', Object(BidderPhone)) #5 {main} thrown in /var/www/classes/PdoDatabase.php on line 59

所以我在id存在之后就失去了事务，这是因为我在做其他编程，而不是准备查询和执行它们吗？我还有什么需要知道的吗？在过去的两天里，我一直在努力解决这个问题。问题是，在实际执行一些查询之前，我确实需要能够开始我的事务并做一些工作。有办法做到这一点吗？

提前感谢您的帮助。

编辑因此，我对代码进行了一些重大更改，并能够更准确地确定何时丢失活动事务。

我的保存方法看起来像这个

public function save($table, $object, $old_object = null){
    echo "in save ".$this->transactionStarted()."<br />";
    if($object->_id != ''){
        echo "before update ".$this->transactionStarted()."<br />";
        //return $this->update($table, $object, $old_object, $transaction);
        if($this->update($table, $object, $old_object)){
            echo "update true ".$this->transactionStarted()."<br />";
            return true;
        } else {
            echo "update false ".$this->transactionStarted()."<br />";
            return false;
        }
    } else {
        echo "before create ".$this->transactionStarted()."<br />";
        //return $this->create($table, $object, $transaction);
        if($this->create($table, $object)){
            echo "create true ".$this->transactionStarted()."<br />";
            return true;
        } else {
            echo "create false ".$this->transactionStarted()."<br />";
            return false;
        }
    }
}

在这种特殊的情况下，有一个来自对象的_id，所以$this->update是我们在这里调试的更新方法

private function update($table, $object, $old){
    echo "in update ".$this->transactionStarted()."<br />";
    $audit = new PdoDatabase;
    echo "after new ".$this->transactionStarted()."<br />";
    $aq = "insert into audit_trails 
            (table_name, table_id, user_id, field_name, original_value, new_value) values
            (:table_name, :table_id, :user_id, :field_name, :original_value, :new_value)";
    echo "before query ".$this->transactionStarted()."<br />";
    $audit->query($aq);
    echo "after query ".$this->transactionStarted()."<br />";
    //$update = new PdoDatabase;    
    $binding = array();
    echo "before field_names ".$this->transactionStarted()."<br />";
    $field_names = self::getFields($table);
    echo "after field_names ".$this->transactionStarted()."<br />";
    $uc = new UserConfig;
    $uc->getConfig();
    $user = $uc->getList(0);
    echo "before foreach ".$this->transactionStarted()."<br />";
    foreach($field_names as $field){
        $thisField = "_".$field['Field']."<br>";
        $getField = 'get'.self::to_camel_case($field['Field']);
        $method = $getField;
        $class = self::to_camel_case($table);
        $field_list = '';
        if($field['Field'] == 'id'){
            $where = 'where id = :id';
            $binding[':id'] = ($object->$getField());
        } else {
            if(method_exists($class, $method)){
                if($object->$getField() != $old->$getField()){
                    $field_list .= $field['Field']."= :".$field['Field'].", ";
                    $binding[':'.$field['Field']] = $object->$getField();
                    $audit->bind(':table_name', $table);
                    $audit->bind(':table_id', $object->getId());
                    $audit->bind(':user_id', $user->getUserId());
                    $audit->bind(':field_name', $thisField);
                    $audit->bind(':original_value', $object->$getField());
                    $audit->bind(':new_value', $old->$getField());
                    echo "before audit execute ".$this->transactionStarted()."<br />";
                    $audit->execute();
                    echo "after audit execute ".$this->transactionStarted()."<br />";
                }
            }
        }
    }
    echo "before binding ".$this->transactionStarted()."<br />";
    if(count($binding) > 1){
        $q = "update ".self::singularToPlural($table)." set ";
        foreach($binding as $key => $value){
            if($key != ':id'){
                $q .= str_replace(':', '', $key)." = ".$key.", ";
            }
        }
        $q = rtrim($q, ", ");
        $q .= ' '.$where;
        //$update->query($q);
        echo "before this query ".$this->transactionStarted()."<br />";
        $this->query($q);
        echo "after this query ".$this->transactionStarted()."<br />";
        /*if($transaction && !$this->_stmt->inTransaction()){
            $this->_stmt->beginTransaction();
        }*/
        foreach($binding as $key => $value){
            //$update->bind($key, $value);
            $this->bind($key, $value);
        }
        //$update->bind($id);
        //return $update->execute();
        echo "before this execute ".$this->transactionStarted()."<br />";
        $stupid = $this->execute();
        echo "after this execute ".$this->transactionStarted()."<br />";
        return $stupid;
    } else {
        echo "before return true ".$this->transactionStarted()."<br />";
        return true;
    }
}

输出为

first 1
in save 1
before update 1
in update 1
after new 1
before query 1
after query 1
before field_names 1
before execute 1
after execute 1
after field_names 1
before foreach 1
before audit execute 1
before execute 1
after execute 1
after audit execute 1
before binding 1
before this query 1
after this query 1
before this execute 1
before execute 1
after execute 1
after this execute 1
update true
the save 1
second
after save
before commit
Fatal error: Uncaught exception 'PDOException' with message 'There is no active transaction' in /var/www/classes/PdoDatabase.php:86 Stack trace: #0 /var/www/classes/PdoDatabase.php(86): PDO->commit() #1 /var/www/admin/data/post_data.php(403): PdoDatabase->commit() #2 {main} thrown in /var/www/classes/PdoDatabase.php on line 86

从这一点我可以看到，当我们从更新返回到保存方法时，活动事务丢失了，我只是不确定为什么会这样。

再次感谢。

编辑添加getBidderById函数

public function getBidderById($bidder_id){
    $pdo = new PdoDatabase;
    $q = "select *
            from bidders Bidder
            where Bidder.id = :bidder_id
            limit 1";
    $pdo->query($q);
    $pdo->bind(":bidder_id", $bidder_id);
    $this->_bidders = $pdo->execute('Bidder');
    if(!empty($this->_bidders)){
        return true;
    } else {
        return false;
    }
}

编辑添加创建方法

private function create($table, $object){
    //$insert = new PdoDatabase;
    $field_names = self::getFields($table);
    foreach($field_names as $field){
        $getField = 'get'.self::to_camel_case($field['Field']);
        $method = $getField;
        $class = self::to_camel_case($table);
        if(method_exists($class, $method)){
            if($field['Field'] != 'id'){
                $fields = $field['Field'].", ";
                $binding_fields = ":".$field['Field'].", ";
                $binding[':'.$field['Field']] = $object->$getField();
            }
        }
    }
    $fields = rtrim($fields, ", ");
    $binding_fields = rtrim($binding_fields, ", ");
    $iq = "insert into ".self::singularToPlural($table)." 
            (".$fields.") values 
            (".$binding_fields.")";
    $this->query($iq);
    /*if($transaction && !$this->_stmt->inTransaction()){
        $this->_stmt->beginTransaction();
    }*/
    foreach($binding as $key => $value){
        $this->bind($key, $value);
    }
    if($this->execute()){
        $object->setId($this->getConnection()->lastInsertId());
        return true;
    } else {
        return false;
    }
}

Hmz，我注意到您正在一个函数中实例化PdoDatabase，并使用$this->transactionStarted（）。

这可能不是问题，但由于您使用的是持久连接，因此可能在其他类中启动一个新事务，从而导致对正在运行的事务的隐式提交。

    if($this->create($table, $object)){
        echo "create true ".$this->transactionStarted()."<br />";
        return true;
    }

如果在此函数中使用DDL语句（CREATE、ALTER、DROP、TRUNCATE等），则还将应用提交

MySQL中的某些语句会导致隐式提交。您可能正在进行的任何事务都已提交。例如，所有DDL语句都是这样做的。看见https://dev.mysql.com/doc/refman/5.6/en/implicit-commit.html了解更多信息。

令人惊讶的是，很难知道您的会话中是否有活动事务。在导致隐式提交的语句和查询可以是"commit"（不通过任何commit（）函数，而是通过query（）函数）的可能性之间，客户端无法确定是否仍有事务在进行。

这个问题对那些试图创建可重用DBAL的开发人员来说是一种祸害。

另请参阅我对"如何检测事务已启动？"的回答？

重新评论：

对于MySQL，PDO::inTransaction()不可靠，因为PDO-MySQL驱动程序没有实现方法mysql_handle_in_transaction()。MySQL C API不支持查询当前会话的事务状态。

因此，PDO类试图通过使用一个内部变量来进行最佳猜测，该变量在调用$dbh->beginTransaction()时设置为1，在调用$dbh->commit()或$dbh->rollback()时设置为0。

但是，如果DDL语句导致隐式提交，则驱动程序不会收到任何事务结束的通知。因此，PDO中的内部变量可能与现实不同步。如果您调用$dbh->query('COMMIT')，绕过PDO函数进行事务控制，也可能发生这种情况。

其他PDO驱动程序，例如PostgreSQL驱动程序，确实实现了获取当前事务状态的方法。

在这种情况下，我并不是说这就是你问题的原因。但是，尝试检测客户端中的事务状态并不总是有效的。

我不知道你的案子发生了什么。您仍然有几行调试输出没有共享代码。

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