Question

我的主页上有两个按钮，一个是超时，另一个是超时，我想防止用户/学生使用相同的ID进行登录，如果他/他没有在上次输入超时时创建有效的条目。希望您能够帮助我。

这是我的php代码：

<?php 

include_once('connection.php');
if(isset($_POST['submit0'])){
    $rfid = $_POST['rfid'];
    $time=date("H:i:s");
    $sql = mysqli_query($conn, "SELECT * FROM stud WHERE rfid_num = '$rfid'");
    $count = mysqli_num_rows($sql);

    if ($count == 0 ) {
        header("location:notexist.php");
    } elseif (empty($row['timeout'])) {
        header("location:page say the user/student need to put timeout first before time-in again");
    } else {
        while( $row = mysqli_fetch_array($sql)) {
            $rfid=$row['rfid_num'];
            $id=$row['id'];
            $name0 = $row['name'];
            $course0 = $row['course'];
            $image = $row['image'];

            $InsertSql = "INSERT INTO student_att(rfid_num,id,name,course,image,timein) VALUES ('$rfid','$id','$name0','$course0','$image','$time')";
            $res = mysqli_query($conn, $InsertSql); 
        }
    }
}
?>

Answer 1

这是我的答案，想分享一下，我只添加选择student_att表获取数据并检查超时列是否为空。

<?php 

include_once('connection.php');
if(isset($_POST['submit0'])){
$rfid = $_POST['rfid'];
$time=date("H:i:s");
$sql = mysqli_query($conn,"select * from stud where rfid_num ='$rfid' ");
$count = mysqli_num_rows($sql);
if ($count == 0) {
            header("location:notexist.php");
        }else{
         while( $row = mysqli_fetch_array($sql)) {
                  $rfid=$row['rfid_num'];
                  $id=$row['id'];
                   $name0 = $row['name'];
                       $course0 = $row['course'];
                    $image = $row['image'];

                $sql1 = mysqli_query($conn,"select * from student_att where rfid_num ='$rfid' order by number DESC limit 1 ");
                 while( $row = mysqli_fetch_array($sql1)) {

             if(empty($row['timeout'])){
                   header("location:logout.php");
                 }else{


         $InsertSql = "INSERT INTO student_att(rfid_num,id,name,course,image,timein) VALUES ('$rfid','$id','$name0','$course0','$image','$time')";
        $res = mysqli_query($conn, $InsertSql); 
        }
        }

        }

}
}
?>

如果用户/学生没有超时，则防止插入相同的ID

1 个答案: