php - undefined variable - 作品

Question

我有一个脚本可以更新数据库中的日期字段。 (已购买)。

我还在另一部分中使用该数据更新第二个日期字段，该字段采用输入日期并添加 6 年 $duedate。它工作正常，但我收到变量 purchased 的 Undefined Variable 错误。

$duedate = new DateTime($purchased);
$duedate->add(new DateInterval('P6Y'));

我尝试使用下面的定义它，但它停止更新第二个字段并且不会抛出任何错误。

$duedate = new DateTime($_POST['purchased']);
$duedate->add(new DateInterval('P6Y'));

$purchased = "";
$duedate = new DateTime($purchased);
$duedate->add(new DateInterval('P6Y'));

$purchased = null;
$duedate = new DateTime($purchased);
$duedate->add(new DateInterval('P6Y'));

$purchased = isset($_POST['purchased']) ? $_POST['purchased'] : '';
$duedate = new DateTime($purchased);
$duedate->add(new DateInterval('P6Y'));

$purchased = !empty($_POST['purchased']) ? $_POST['purchased'] : '';
$duedate = new DateTime($purchased);
$duedate->add(new DateInterval('P6Y'));

代码

$barcode = $_GET['barcode'];
$stmt = $conn->prepare("SELECT * FROM assets WHERE barcode=:barcode");
$stmt->execute(array(":barcode"=>$barcode));

$row=$stmt->fetch(PDO::FETCH_ASSOC);

if (isset($_POST['update'])) {
    $category = isset($_POST['category']) ? $_POST['category'] : null;
    $manufactuer = isset($_POST['manufactuer']) ? $_POST['manufactuer'] : null;
    $model = isset($_POST['model']) ? $_POST['model'] : null;
    $serial = isset($_POST['serial']) ? $_POST['serial'] : null;
    $itemcondition = isset($_POST['itemcondition']) ? $_POST['itemcondition'] : null;
    $locationb = isset($_POST['locationb']) ? $_POST['locationb'] : null;
    $locationr = isset($_POST['locationr']) ? $_POST['locationr'] : null;
    $comments = isset($_POST['comments']) ? $_POST['comments'] : null;
    $purchased = isset($_POST['purchased']) ? $_POST['purchased'] : null;
    $retired = isset($_POST['retired']) ? $_POST['retired'] : null;
    $stolen = isset($_POST['stolen']) ? $_POST['stolen'] : null;
    $latest = isset($_POST['latest']) ? $_POST['latest'] : null;
    $due = isset($_POST['due']) ? $_POST['due'] : null;

    $sql_part = array();
    $prepare = array();
    if ($category){
        $sql_part[] = 'category = :category';
        $prepare[':category'] = $category;
    }
    if($manufactuer){
        $sql_part[] = 'manufactuer = :manufactuer';
        $prepare[':manufactuer'] = $manufactuer;
    }
    if($model){
        $sql_part[] = 'model = :model';
        $prepare[':model'] = $model;
    }
    if($serial){
        $sql_part[] = 'serial = :serial';
        $prepare[':serial'] = $serial;
    }
    if($itemcondition){
        $sql_part[] = 'itemcondition = :itemcondition';
        $prepare[':itemcondition'] = $itemcondition;
    }
    if($locationb){
        $sql_part[] = 'locationb = :locationb';
        $prepare[':locationb'] = $locationb;
    }
    if($locationr){
        $sql_part[] = 'locationr = :locationr';
        $prepare[':locationr'] = $locationr;
    }
    if($comments){
        $sql_part[] = 'comments = :comments';
        $prepare[':comments'] = $comments;
    }
    if($purchased){
        $sql_part[] = 'purchased = :purchased';
        $prepare[':purchased'] = $purchased;
    }
    if($retired){
        $sql_part[] = 'retired = :retired';
        $prepare[':retired'] = $retired;
    }
    if($stolen){
        $sql_part[] = 'stolen = :stolen';
        $prepare[':stolen'] = $stolen;
    }
    if($latest){
        $sql_part[] = 'latest = :latest';
        $prepare[':latest'] = $latest;
    }
    if($due){
        $sql_part[] = 'due  =:due';
        $prepare[':due'] = $due;
    }

    $prepare[':barcode'] = $barcode;

    if(count($sql_part)){
        $sql = 'UPDATE assets SET ';
        $sql .= implode(', ', $sql_part);
        $sql .= ' WHERE barcode = :barcode';

        $stmt = $conn->prepare($sql);

        if($stmt){
            $result = $stmt->execute($prepare);
            $count = $stmt->rowCount();
            header('Location: ./usearch.php');
            exit;
        }
    }
}

$duedate = new DateTime($purchased);
$duedate->add(new DateInterval('P6Y'));

    <input type="hidden" name="due" value="<?php echo $duedate->format('Y-m-d'); ?>">

文件有 261 行，所以我已经包含了相关的片段，如果需要可以添加完整的文件。

Answer 1

文件末尾的这些行:

$duedate = new DateTime($purchased);
$duedate->add(new DateInterval('P6Y'));

    <input type="hidden" name="due" value="<?php echo $duedate->format('Y-m-d'); ?>">

正在抛出 undefined variable 通知，因为它位于条件语句之外，并且在页面加载后立即发出通知。

这就是我从这一切中得到的。

我发布了这个，因为我很早就对此发表了评论。

因此，使用条件语句/三元运算符。

一旦有它的值(value)，它就会完成它的工作。