“注意：当我看到对象存在时，试图获取非对象的属性”

Question

Just trying to get some rows out of a database and loop through but I am get the non-object error.

    $db = classes_pdoDB::getConnection();
    $query = "SELECT *
              FROM lesson
              WHERE userID=:userID";
    $stmt = $db->prepare($query);
    $stmt->execute(array(':userID' => $userID));
    $lessons = $stmt->fetchAll();

    foreach ($lessons as $lesson){

        print_r ($lesson);

        $page->addToBody ("<div class=\"editLessonEntry\">
            <p><a href=\"editLesson.php?lessonid=" . $lesson->lessonID . "\" >" . $lesson->lessonTitle . "</a></p>
            <p>" . $lesson->lessonSummary . " </p>
        </div>
        <hr />");

    }

Not really certain what the error is because the print_r is working fine and showing me all the objects which I am trying to include. I'm sure like all of my questions I am just overlooking something incredibly simple. But I really cannot see it. I have other similar functions through the site which work fine and I can't see the differences really.

Answer 1

fetchAll() returns an array unless you have specified the class to return with PDO::FETCH_CLASS. So in this case, you should be accessing $lesson by array elements rather than object properties:

$lessons = $stmt->fetchAll();

foreach ($lessons as $lesson){

    print_r ($lesson);

    $page->addToBody ("<div class=\"editLessonEntry\">
        <p><a href=\"editLesson.php?lessonid=" . $lesson['lessonID'] . "\" >" . $lesson['lessonTitle'] . "</a></p>
        <p>" . $lesson['lessonSummary'] . " </p>
    </div>
    <hr />");
 }

If you must get these as an object and have a Lesson class, you can do it this way:

$lessons = $stmt->fetchAll(PDO::FETCH_CLASS, "Lesson");

This assumes the Lesson class takes no parameters to its constructor. This is detailed in the fetchAll() documentation.