Download file from database path (given upload scripts)

Good Day Forums,

I have manage to make a script to upload file in database and its working. I will share to you the codes so for other viewers and readers to use also.

if($result){
            if($_FILES['LRCard']['name'] != ""){
                $filename = $_FILES['LRCard']['name'];
                $ext = strrchr($filename,".");
                $LRCardname = $student_id;
                $LRCardname .="_". $filename; 
                if($ext ==".jpg" || $ext ==".jpeg" || $ext ==".JPG" || $ext ==".JPEG" || $ext ==".gif" || $ext ==".GIF"){
                    $size = $_FILES['LRCard']['size'];
                    if($size > 0 && $size < 5000000){
                        $archive_dir = "LRCards";
                        $userfile_tmp_name = $_FILES['LRCard']['tmp_name'];
                        if(move_uploaded_file($userfile_tmp_name, "$archive_dir/$LRCardname")){
                            /*
                                if LRC is successfully uploaded then LRC is stored in database.
                            */
                            mysql_query("update student_information set LRCard='$LRCardname' where student_id='$student_id'", $link_id); 
                            $flag = "success"; 
                            if(mysql_error()!=null){
                                die(mysql_error());
                            }
 
                        }
                        else{
                            if(file_exists('LRCard/' . $LRCardname)) {
                                unlink('LRCards/' . $LRCardname); 
                            }
                            rollbackData();
                        }
                    }
                    else{
                        if(file_exists('LRCards/' . $LRCardname)) {
                            unlink('LRCard/' . $LRCardname); 
                        }
                        rollbackData();
                        die("You can upload LRCard of 5 MB size only. Please, try again.");
                    }
                }
                else{
                    if(file_exists('LRCards/' . $LRCardname)) {
                        unlink('LRCards/' . $LRCardname); 
                    }
                    rollbackData();
                    die("You can upload LRCard of .jpg, .jpeg, .gif extensions only. Please, try again. ");
                }
            }     
        }
        else{
            $flag="error";
        }
        if($flag == "success"){
            mysql_query(" COMMIT ");
            $flag="success";
            if(mysql_error() != null){
                die(mysql_error());
            }
        }  

Code (markup):

Now, my problem is how to make a Php script to DOWNLOAD this uploaded file considering the
1. file path
2. file name
3. file extension.
4. student_id (to determine the specific file from a specific student)

The images are stored in the

the-http://localhost/a/LRCards/

My plan is to make a download button which hyperlink to download.php and after clicking that button the specified file to a specific student id will automatically be downloaded by the browser.

Please advise..