Question

我有一个表单，其中包含学生姓名复选框，显示在课程详细信息页面上。如果您提交表格，则允许您将学生分配到班级。

如果您重新访问该页面，它会记住哪些学生已被分配到该课程，并自动检查其相应的框。该表格允许您检查其他学生并提交表格，他们将添加到课程中。

我遇到的麻烦实际上是将学生从课堂上移除。具体来说，我如何跟踪哪些学生已被取消选中＆＃34;未经检查＆＃34;在类详细信息页面上，并将它们传递给表单操作页面，然后我可以在其上循环SQL DELETE语句？

以下是我一直在玩的代码：

$class_id = $_GET['class_id'];
$tid = $_POST['teachers'];
$student_count = $_GET['student_count'];

mysqli_query($db,"UPDATE class SET teacher_id = $tid WHERE id=$class_id");

if (isset($_POST['students'])) {
    $students = $_POST['students'];
    foreach ($students as $student_id) {
        if (count($students) < $student_count) {
            foreach (/*student that was unchecked from the class.php form*/) {
                //delete statement
            }
            break;
        } else {
            mysqli_query($db, "UPDATE student_class SET student_id = $student_id WHERE class_id = $class_id");
            mysqli_query($db,"INSERT INTO student_class (student_id, class_id) VALUES ($student_id, $class_id)");
        }
    }
}

Answer 1

当取消选中时，复选框不会在$_POST或$_GET数组中生成一个条目。

但您只需删除数据库中的每个条目，即不再进行检查。（如果您的表单包含完整的枚举，那么将取消选中！）

$checkedStudents = array() //Exemplary: depends on the format of $students. If just an id-array, this can be skipped. foreach ($students as $student_id) { $checkedStudents[] = $student_id; } $inStr = "(" + implode(",",$checkedStudents) + ")"; $query = "DELETE FROM student_class WHERE class_id = $class_id AND student_id NOT IN ".$inStr;

如何让我的表单记住哪些值已“未选中”？

1 个答案: