Question

我使用的是典型的PDO try / catch子句，除了一个方面：WHERE子句外，它应该按预期工作。

这是我的代码：

$pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);

try {
    $cancel_query = "UPDATE table SET active = 0 WHERE id = $request_id";
    $cancel_stmt = $pdo->prepare($cancel_query);
    $cancel_stmt->execute();

    $message = "That request was successfully canceled.";

} catch (PDOException $e) {
    $message = 'This request was not canceled. Something went wrong. ' . $e->getMessage();
}

$pdo = null;

echo $message;

这通常会捕获错误，例如，如果我故意输入了错误的表名或列名。但是，如果我输入了不存在的$ request_id，则该消息将指示成功。由于没有更新任何内容，因为WHERE子句没有要更新的行，所以从业务角度来说，捕获异常是理想的选择。

如果不进行更新，是否有办法抛出错误？

Answer 1

如果更新未成功完成，将引发异常（或者，如果您不想引发异常，则设置$message会有所不同）

$pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);

try {
    $cancel_query = "UPDATE table SET active = 0 WHERE id = $request_id";
    $cancel_stmt = $pdo->prepare($cancel_query);
    $cancel_stmt->execute();

    if ($cancel_stmt->rowCount() < 1) //Count the number of affected rows, if less than 1 then none
    {
        throw new Exception('Oh no :('); // of course, write a proper error message
        // $message = "something is wrong"; // if you don't want to throw, set $message and use an else statement for the success message
    }
    else
    {
        $message = "That request was successfully canceled.";
    }

} catch (PDOException $e) {
    $message = 'This request was not canceled. Something went wrong. ' . $e->getMessage();
}
catch (Exception $ex)
{
   $message = 'This request was canceled. Something went wrong. ' . $ex->getMessage();
}

$pdo = null;

echo $message;

WHERE子句的PDO try / catch不会捕获错误

1 个答案: