Question

我是PHP新手，正在从事家庭作业。当我单击<aside>中的链接时，数据应该更新了。单击该链接只会更新地址栏中的查询参数。查询参数可以很好地更新，但数据保持不变。

以下是相关代码：

// index.php

<?php
require_once('database.php');

// Get category ID
$course_id = filter_input(INPUT_GET, 'course_id',
    FILTER_VALIDATE_INT);
if ($course_id == NULL || $course_id == FALSE) {
    $course_id = 'cs601';
}

// Get name for selected category
$queryCourse = 'SELECT * FROM sk_courses WHERE courseID = :course_id';
$queryCourseStatement = $db->prepare($queryCourse);
$queryCourseStatement->bindValue(':course_id', $course_id);
$queryCourseStatement->execute();

$course = $queryCourseStatement->fetch();
$course_name = $course['courseName'];

$queryCourseStatement->closeCursor();


// Get all courses
$queryCourses = 'SELECT * FROM sk_courses ORDER BY courseID';
$queryCoursesStatement = $db->prepare($queryCourses);
$queryCoursesStatement->execute();

$courses = $queryCoursesStatement->fetchAll();

$queryCoursesStatement->closeCursor();

// Get products for selected category
$queryStudents = 'SELECT * FROM sk_students WHERE courseID = :course_id ORDER BY studentID';
$queryStudentsStatement = $db->prepare($queryStudents);
$queryStudentsStatement->bindValue(':course_id', $course_id);
$queryStudentsStatement->execute();

$students = $queryStudentsStatement->fetchAll();

$queryStudentsStatement->closeCursor();

?>

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css"
          integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
    <title>MMelvin HW5</title>
</head>
<body>
<main class="container">
    <h1 class="display-6">Course Manager</h1>
    <hr>

    <div class="d-flex justify-content-between">

        <aside>
            <h2 class="display-6">Courses</h2>
            <nav>
                <ul class="list-group">
                    <?php foreach ($courses as $course) : ?>
                        <li class="list-group-item">
                            <a href="?course_id=<?php echo $course['courseID']; ?>">
                                <?php echo $course['courseID']; ?>
                            </a>
                        </li>
                    <?php endforeach; ?>
                </ul>
            </nav>
        </aside>

        <section>
            <h2 class="display-6"><?php echo $course_id . ' - ' . $course_name; ?></h2>

            <table class="table table-striped table-bordered">
                <thead>
                <tr>
                    <th class="text-center">First Name</th>
                    <th class="text-center">Last Name</th>
                    <th class="text-center">Email</th>
                    <th></th>
                </tr>
                </thead>
                <tbody>
                <?php foreach ($students as $student) : ?>
                    <tr>
                        <td class="text-center"><?php echo $student['firstName']; ?></td>
                        <td class="text-center"><?php echo $student['lastName']; ?></td>
                        <td class="text-center"><?php echo $student['email']; ?></td>
                        <td class="text-center">
                            <form action="delete_student.php" method="post">
                                <input class="btn btn-danger" type="submit" name="student_id"
                                       value="Delete">
                            </form>
                        </td>
                    </tr>
                <?php endforeach; ?>
                </tbody>
            </table>

            <p><a href="add_student_form.php">Add Student</a></p>
            <p><a href="course_list.php">List courses</a></p>
        </section>

    </div>
</main>
</body>
</html>

// database.php
<?php

$dsn = 'mysql:host=localhost;dbname=cs602';
$username = 'cs602*********';
$password = '************';

try {
    $db = new PDO($dsn, $username, $password);
} catch (PDOException $e) {
    $error_message = $e->getMessage();
    include('../../../MAMP/logs/mysql_error_log.err');
    exit();
}

下面是一些屏幕截图，可以更好地说明正在发生的事情。

在初始页面加载时：

点击cs602之后：

这些框应已使用数据库中的相关信息进行更新。

在此先感谢您的帮助。

更改查询参数时，我不断从数据库中获取过时的数据

0 个答案: