Question

我有问题。我想要一些数据输出我的数据库。我在这里有两个页面的类别。我希望他能在数据库中显示所有内容。我有第二页。这是我的课程。我已经尝试了一个关于categorie.php的foreach，但是如果我这样做，那么他将数据库中的1个相同的数据显示为4次，而不是另一个数据。您可以在下面看到我的代码。我希望你能帮助我。

谢谢。

这是我的categorie.php

<?php
require_once '../app/functions/second.php';
require_once '../app/db/dbpassword.php';
require_once 'include/head.php';


if (isset($_GET['categorie']) && !empty($_GET['categorie'])) {
    $id = $_GET['categorie'];
    $dbh = new PDO("mysql:host=$host; dbname=$dbname;", $usernamedb, 
$passworddb);
    $cate = new Categorie($dbh);
    $cate->loadCate($id);
    // $page->loadId($id);
    $categorie = $cate->getCategorie();
    $titel = ucwords($categorie);

?>

<h2 class="center_h2"><?= $titel ?></h2>
<?php foreach ($cate as $key) {
        $titelart = $cate->getTitel();
    $beschrijving = $cate->getBeschrijving();
    $plaatje = $cate->getImage();
    $id = $cate->getId();
    var_dump($titelart);
} ?>


<?php 
} else {
    echo "Dit bericht is verwijderd of is verplaats.";
}
require_once 'include/footer.php';
?>

这是我的课程页面

    <?php
    class Categorie {
    protected $dbh;

    public function __construct($new_dbh){
        $this->dbh = $new_dbh;
    }

    public function loadCate($cate){
        $query = $this->dbh->prepare('SELECT * FROM schilderijen WHERE categorie=?');
        $query->execute(array($cate));
        while ($row = $query->fetch(PDO::FETCH_OBJ)) {
            $this->id = $row->id;
        $this->categorie = $row->categorie;
        $this->titel = $row->titel;
        $this->beschrijving = $row->beschrijving;
        $this->plaatje = $row->plaatje;
        }


    }

    public function getId(){
        return $this->id;
    }

    public function getCategorie(){
        return $this->categorie;
    }

    public function getTitel(){
        return $this->titel;
    }

    public function getBeschrijving(){
        return $this->beschrijving;
    }

    public function getImage(){
        return $this->plaatje;
    }
}
?>

Answer 1

好的，所以你的班级使用有问题。在SQL请求之后的while中，将值应用于$this->id = $row->id;之类的实例变量，但此变量将使用下一行值重写。

对SQL请求使用static函数并返回Categorie这样的数组：

class Categorie {
    protected $id, $categorie, $title, $beschrijving, $plaatje;

    public function __construct($id, $categorie, $title, $beschrijving, $plaatje){
        $this->id = $id;
        $this->categorie = $categorie;
        $this->title = $title;
        $this->beschrijving = $beschrijving;
        $this->plaatje = $plaatje;
    }

    public static function loadCate($dbh, $cate){
        $query = $dbh->prepare('SELECT * FROM schilderijen WHERE categorie=?');
        $query->execute(array($cate));

        $res = array();
        while ($row = $query->fetch(PDO::FETCH_OBJ)) {
            $res[] = new Categorie($row->id, $row->categorie, $row->titel, $row->beschrijving, $row->plaatje);
        }

        return $res;
    }

    public function getId(){
        return $this->id;
    }

    public function getCategorie(){
        return $this->categorie;
    }

    public function getTitle(){
        return $this->title;
    }

    public function getBeschrijving(){
        return $this->beschrijving;
    }

    public function getImage(){
        return $this->plaatje;
    }
}

你可以这样使用它：

$categories = Categorie::loadCate($dbh, $id);
foreach($categories as $categorie){
    var_dump($categorie->getTitle());
}

如何使用foreach和class获取数据库之外的所有内容

1 个答案: