PHP PDO MySQL事务代码结构

问题描述

我正在尝试使用PHP/PDO在MySQL中设置我的第一笔交易...

I am trying to set up my first transaction in MySQL using PHP/PDO...

我只想问一个简单的问题，确定上一个查询是否成功的最佳方法是什么?这是我现在拥有的，但是我宁愿找到一种使用if语句测试查询的方法.

I just have a quick question, what is the best way to determine if the previous query was successful or not? Here is what I have right now, but I would rather find a way to test the query with an if statement.

这几乎是模拟代码，试图获得有效的模型..我知道$ results不能有效地测试任何东西的好坏.时间到了.

This is pretty much mock up code to try to get a working model.. I know $results isn't effectively testing if anything was good or bad.. i have it there more as a place holder for the real deal when the time comes..

if ($_POST['groupID'] && is_numeric($_POST['groupID'])) {
    $sql = "SET AUTOCOMMIT=0";
    $dbs = $dbo->prepare($sql);
    $dbs->execute();

    $sql = "START TRANSACTION";
    $dbs = $dbo->prepare($sql);
    $dbs->execute();

    $sql = "DELETE FROM users_priveleges WHERE GroupID=:groupID";
    $dbs = $dbo->prepare($sql);
    $dbs->bindParam(":groupID", $_POST['groupID'], PDO::PARAM_INT);
    $dbs->execute();

    try {
        $sql = "DELETE FROM groups WHERE GroupID=:groupID LIMIT 1";
        $dbs = $dbo->prepare($sql);
        $dbs->bindParam(":groupID", $_POST['groupID'], PDO::PARAM_INT);
        $dbs->execute();

        $results["error"] = null;
        $results["success"] = true;

        try {
            $sql = "DELETE FROM users WHERE Group=:groupID";
            $dbs = $dbo->prepare($sql);
            $dbs->bindParam(":groupID", $_POST['groupID'], PDO::PARAM_INT);
            $dbs->execute();

            $results["error"] = null;
            $results["success"] = true;

            $sql = "COMMIT";
            $dbs = $dbo->prepare($sql);
            $dbs->execute();
        }
        catch (PDOException $e) {
            $sql = "ROLLBACK";
            $dbs = $dbo->prepare($sql);
            $dbs->execute();

            $results["error"] = "Could not delete associated users! $e";
            $results["success"] = false;
        }
    }
    catch (PDOException $e)
    {
        $sql = "ROLLBACK";
        $dbs = $dbo->prepare($sql);
        $dbs->execute();

        $results["error"] = "COULD NOT REMOVE GROUP! $e";
        $results["success"] = false;
    }
}

推荐答案

一些一般说明:除非使用修改参数值的过程，否则不要使用bindParam()因此，use bindValue(). bindParam()接受参数值作为引用变量.这意味着您不能执行$stmt->bindParam(':num', 1, PDO::PARAM_INT);-这会引发错误.另外，PDO具有自己的控制交易的功能，您无需手动执行查询.

Some general notes:Don't use bindParam() unless you use a procedure that modifies the parameter's valueTherefore, use bindValue(). bindParam() accepts argument value as a referenced variable. That means you can't do $stmt->bindParam(':num', 1, PDO::PARAM_INT); - it raises an error.Also, PDO has its own functions for controlling transactions, you don't need to execute queries manually.

我稍微重写了您的代码，以阐明如何使用PDO:

I rewrote your code slightly to shed some light on how PDO can be used:

if($_POST['groupID'] && is_numeric($_POST['groupID']))
{
    // List the SQL strings that you want to use
    $sql['privileges']  = "DELETE FROM users_priveleges WHERE GroupID=:groupID";
    $sql['groups']      = "DELETE FROM groups WHERE GroupID=:groupID"; // You don't need LIMIT 1, GroupID should be unique (primary) so it's controlled by the DB
    $sql['users']       = "DELETE FROM users WHERE Group=:groupID";

    // Start the transaction. PDO turns autocommit mode off depending on the driver, you don't need to implicitly say you want it off
    $pdo->beginTransaction();

    try
    {
        // Prepare the statements
        foreach($sql as $stmt_name => &$sql_command)
        {
            $stmt[$stmt_name] = $pdo->prepare($sql_command);
        }

        // Delete the privileges
        $stmt['privileges']->bindValue(':groupID', $_POST['groupID'], PDO::PARAM_INT);
        $stmt['privileges']->execute();

        // Delete the group
        $stmt['groups']->bindValue(":groupID", $_POST['groupID'], PDO::PARAM_INT);
        $stmt['groups']->execute();

        // Delete the user
        $stmt['users']->bindParam(":groupID", $_POST['groupID'], PDO::PARAM_INT);
        $stmt['users']->execute();

        $pdo->commit();
    }
    catch(PDOException $e)
    {
        $pdo->rollBack();

        // Report errors
    }
}

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