如果输入为空，则保留图像路径

我有一个表单，有一些输入，我想在数据库中进行一些编辑。我想如果存在一个图片在数据库中保持它不与空白空间取代。这是我的代码

<?php
include "../../../config/config.php";
session_start();
if (isset($_GET['car'])) {
    $car = $_GET['car'];
} else {
    die("Not found");
}

if (isset($_POST['submit-edit'])) {

    $title = mysqli_real_escape_string($con, $_POST['title-edit']);
    $description = mysqli_real_escape_string($con, $_POST['description-edit']);
    $category = mysqli_real_escape_string($con, $_POST['category-edit']);

    /* ----------------------- MAIN IMAGE  -------------------------- */
    $target_dir = "../../../img/found/thumbs-category/";
    $target_file2 = "" . basename($_FILES["img-edit"]["name"]);
    $target_file = $target_dir . basename($_FILES["img-edit"]["name"]);
    $uploadOk = 1;
    $imageFileType = pathinfo($target_file, PATHINFO_EXTENSION);
    // Check file size
    if ($_FILES["img-edit"]["size"] > 100000) {
        $_SESSION['image-size'] = 1;
        header("Location: /dashboard/views/edit.php?car=$car");
        exit();
    }
//    
    //Allow certain file formats
    if ($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg" && $imageFileType != "gif" && $imageFileType != NULL) {
        $_SESSION['image-format'] = 1;
        header("Location: /dashboard/views/edit.php?car=$car");
        exit();
    }
    // Check if $uploadOk is set to 0 by an error
    if ($uploadOk == 0) {
    } else {
        if (move_uploaded_file($_FILES["img-edit"]["tmp_name"], $target_file)) {

        } else {
            echo "Sorry, there was an error uploading your file.";
            exit();
        }

        $query = "UPDATE cars
            SET title='" . $title . "', text='" . $description . "', image='" . $target_file2 . "', fk_cars_first='" . $category . "' WHERE car=" . $car;

        $result = mysqli_query($con, $query);
//                var_dump($query);
//                exit();
        if ($result) {

            header("Location: /dashboard/views/edit.php?car=$car");
        } else {
//          
            echo "error";
            exit();
            header("Location: /dashboard/views/edit.php?car=$car");
        }
    }
}
?>

更准确地说，我的数据库中有

<>之前标题|描述|图片| fk_category测试更多文本car.jpg调优

当我想编辑数据库时，我使用表单，如果输入type="file"为空，我想保持实际路径不擦除。代码是这样的，我设置了提交按钮，数据库看起来像

<>之前标题|描述|图片| fk_category经过测试!T | | tuning_tex_edited

$query = "UPDATE cars
          SET 
            title='" . $title . "', 
            text='" . $description . "', 
            fk_cars_first='" . $category . "' ";
if(!empty($target_file2)){
    $query .= ", image='" . $target_file2 . "'";
}
$query .= " WHERE car=" . $car;