PHP PDO-没有活动的交易 [英] PHP PDO - There is no active transaction

问题描述

我在php脚本中进行交易时遇到问题.如果其中至少一个失败，我想进行多重查询并能够全部调用它们.在下面，您可以找到我正在使用的脚本的简单示例:

I am having problem with transactions in php script. I would like to make multiply queries and be able to recall them all, if at least one of them fails. Below you can find a simple example of the script I am using:

$tags_input = array(6,4,5);
$conn = new PDO('mysql:host='.DB_HOST.';dbname='.DB_NAME.';charset=utf8',  
DB_USER, DB_PASSW, array(  
    PDO::ATTR_EMULATE_PREPARES => false,  
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'"));

    $conn->beginTransaction();

    $sql = "INSERT INTO projects (id, pr_id, enabled) VALUES ( :val0, :val1, :val2)";
    $stmt = $conn->prepare($sql);  
    if(count($tags_input)>0){
            for($i = 0;$i<count($tags_input);$i++){
                    $stmt->bindValue(':val0', 57); 
                    $stmt->bindValue(':val1', $tags_input[$i]); 
                    $stmt->bindValue(':val2', 'Y'); 
                    $result = $stmt->execute();

            }

    }

    $res1 = $conn->commit();
    $conn->rollBack();

现在，此示例生成一个错误:

Now, this example generates an error:

未捕获的异常"PDOException"，消息为没有活动" 交易"

Uncaught exception 'PDOException' with message 'There is no active transaction'

如果我删除行$conn->rollBack();，该错误消失.因此，我无法理解为什么pdo对象看不到打开的事务(begintransaction和commit不会产生任何错误).我还尝试将rollBack()放入事务中，但没有区别.我仍然收到错误消息没有有效的交易".

If I erase the line $conn->rollBack();, the error disappears. Therefore I cannot understand, why pdo object can't see open transaction (begintransaction and commit do not generate any errors). I also tried putting rollBack() inside the transaction, but made no difference. I was still getting an error 'There is no active transaction'.

我正在InnoDB上运行PHP 5.6和Mysql表.

I am running PHP 5.6 and Mysql tables on InnoDB.

推荐答案

将您的事务代码包装在try-catch语句中.

Wrap your transaction code inside a try-catch statement.

//try {
$tags_input = array(6,4,5);
$conn = new PDO('mysql:host='.DB_HOST.';dbname='.DB_NAME.';charset=utf8',  
DB_USER, DB_PASSW, array(  
    PDO::ATTR_EMULATE_PREPARES => false,  
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'"));
} catch (Exception $e) {
  die("Unable to connect: " . $e->getMessage());
}    
try {  
    $conn->beginTransaction();   
    $sql = "INSERT INTO projects (id, pr_id, enabled) VALUES ( :val0, :val1, :val2)";
    $stmt = $conn->prepare($sql);  
    if(count($tags_input)>0){
            for($i = 0;$i<count($tags_input);$i++){
                    $stmt->bindValue(':val0', 57); 
                    $stmt->bindValue(':val1', $tags_input[$i]); 
                    $stmt->bindValue(':val2', 'Y'); 
                    $result = $stmt->execute();
            }
    }
$res1 = $conn->commit();    
} catch (Exception $e) {
  $conn->rollBack();
  echo "Failed: " . $e->getMessage();
}

编辑

Richard 提供了一个非常基础且直接的答案说明.

A really well-based and straight-forward explanation of the answer was provided by Richard as a comment.

出现错误的原因是因为您试图在已经关闭的事务上关闭该事务. beginTransaction 打开一个，然后 rollBack 或 commit 关闭它.您必须避免对单个 beginTransaction 语句执行两个操作，即提交/回滚，否则会出错.上面的try/catch代码可确保仅执行一个结束语句.

The reason you got error is because you were trying to close a transaction when it was already closed. beginTransaction opens one, and EITHER rollBack OR commit closes it. You have to avoid doing BOTH actions, meaning commit/rollback, for a single beginTransaction statement, or you'll get an error. The above try/catch code ensures that only one closing statement is executed.

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