如果mysqli字段不为空，如何更新

Question

我试图从我的表中更新一个特定的值，从表中获取它们作为行，让我们说名称，但问题是图像，因为我不能传递一个值到输入字段类型=文件
我需要更新数据库中的值只有当有一个值要改变，如果不是不改变已经存在的值。
我的查询看起来像这样，我想知道我可以改变更新图像值只有当有一个值

//image upload + validation
$file          = $_FILES['image'];
$file_name     = $_FILES['image']['name'];//file name
var_dump($file_name);
$file_location = $_FILES['image']['tmp_name']; //temporary location
$file_size     = $_FILES['image']['size'];// size
$file_error    = $_FILES['image']['error'];// error 0 if no error or 1 if there is an error
$temp_extension = explode('.',$file_name);//explode from . file extension, we have file name and extension
$file_extension = strtolower(end($temp_extension)); // extension name (end return the last element of the array)
$allowed_extensions = array('jpg', 'jpeg', 'png', 'pdf');
if (empty($file_name)) {
if (in_array($file_extension, $allowed_extensions)) {
if ($file_error === 0) {
if ($file_size < 15728640) { //15728640b(bytes binary)  15mb mediumblob
$new_file_name = uniqid('',true).".".$file_extension;
// var_dump($new_file_name);
$file_destination = dirname(__FILE__, 2)."/images/".$new_file_name;
move_uploaded_file($file_location, $file_destination);
}else {
echo "Sorry your file size it's too big!";
}
}else {
echo "Sorry, there was an error, try again";
}
}else {
echo "Sorry, your file type is not accepted";
}
}
if(is_array($row)) {
$sql = "UPDATE `accommodation` SET `name` = '{$_POST['name']}', `image` = '$new_file_name', `description` = '{$_POST['description']}', `adress` = '{$_POST['adress']}', `link` = '{$_POST['link']}' WHERE `id` = '{$_POST['id']}'";
mysqli_query(get_connection(), $sql);
var_dump($sql);
// header("Location: admin.php?page=accommodation_list");
}else{
$conn = get_connection();
$sql = "INSERT INTO `accommodation` (`name`, `image`, `description`, `adress`, `link`) VALUES ('{$_POST['name']}', '$new_file_name', '{$_POST['description']}', '{$_POST['adress']}', '{$_POST['link']}')";
mysqli_query($conn, $sql);
$accommodation_id = mysqli_insert_id($conn);
header("Location: admin.php?page=room_add_edit");
}//end if else

这是查询，我需要改变，但我不知道如何....

$sql = "UPDATE `accommodation` SET `name` = '{$_POST['name']}', `image` = '$new_file_name', `description` = '{$_POST['description']}', `adress` = '{$_POST['adress']}', `link` = '{$_POST['link']}' WHERE `id` = '{$_POST['id']}'";

我知道SQL注入，但首先我需要这个查询工作，然后我将在SQL注入工作，我输入地址作为地址，我也必须改变。

我已经把代码改成了这个，但我不知道这是不是一个好方法

//image upload + validation
$file          = $_FILES['image'];
$file_name     = $_FILES['image']['name'];//file name
var_dump($file_name);
$file_location = $_FILES['image']['tmp_name']; //temporary location
$file_size     = $_FILES['image']['size'];// size
$file_error    = $_FILES['image']['error'];// error 0 if no error or 1 if there is an error
$temp_extension = explode('.',$file_name);//explode from . file extension, we have file name and extension
$file_extension = strtolower(end($temp_extension)); // extension name (end return the last element of the array)
$allowed_extensions = array('jpg', 'jpeg', 'png', 'pdf');
if (!empty($file_name)) {
if (in_array($file_extension, $allowed_extensions)) {
if ($file_error === 0) {
if ($file_size < 15728640) { //15728640b(bytes binary)  15mb mediumblob
$new_file_name = uniqid('',true).".".$file_extension;
// var_dump($new_file_name);
$file_destination = dirname(__FILE__, 2)."/images/".$new_file_name;
move_uploaded_file($file_location, $file_destination);
$text1 = "`image` = '$new_file_name',";
}else {
echo "Sorry your file size it's too big!";
}
}else {
echo "Sorry, there was an error, try again";
}
}else {
echo "Sorry, your file type is not accepted";
}
}else {
$text1 = ""; 
}
if(is_array($row)) {
$sql = "UPDATE `accommodation` SET `name` = '{$_POST['name']}', $text1 `description` = '{$_POST['description']}', `adress` = '{$_POST['adress']}', `link` = '{$_POST['link']}' WHERE `id` = '{$_POST['id']}'";
mysqli_query(get_connection(), $sql);
var_dump($sql);
// header("Location: admin.php?page=accommodation_list");
}

Answer 1

您可以简单地使用第三个变量检查文件是否上传。如果文件上传，则保存新文件名，否则保存旧文件名。所以你不会丢失你的文件更新。我假设你在$row中得到整行数据，所以检查下面的代码

$is_file_uploaded = 0;
if (empty($file_name)) {
if (in_array($file_extension, $allowed_extensions)) {
if ($file_error === 0) {
if ($file_size < 15728640) { //15728640b(bytes binary)  15mb mediumblob
$new_file_name = uniqid('',true).".".$file_extension;
// var_dump($new_file_name);
$file_destination = dirname(__FILE__, 2)."/images/".$new_file_name;
move_uploaded_file($file_location, $file_destination);
$is_file_uploaded = 1;
}else {
echo "Sorry your file size it's too big!";
}
}else {
echo "Sorry, there was an error, try again";
}
}else {
echo "Sorry, your file type is not accepted";
}
if(is_array($row)) {
$new_file_name = ($is_file_uploaded == 1) ? $new_file_name : $row['image'];
//your code
}
}

Answer 2

你可以试试:

$new_file_name = "";
if (!empty($file_name)) {
if (in_array($file_extension, $allowed_extensions)) {
if ($file_error === 0) {
if ($file_size < 15728640) { //15728640b(bytes binary)  15mb mediumblob
$new_file_name = uniqid('',true).".".$file_extension;
// var_dump($new_file_name);
$file_destination = dirname(__FILE__, 2)."/images/".$new_file_name;
move_uploaded_file($file_location, $file_destination);
}else {
echo "Sorry your file size it's too big!";
}
}else {
echo "Sorry, there was an error, try again";
}
}else {
echo "Sorry, your file type is not accepted";
}
}
if(is_array($row)) {
if($new_file_name != ""){
$sql = "UPDATE `accommodation` SET `name` = '{$_POST['name']}', `image` = '$new_file_name', `description` = '{$_POST['description']}', `adress` = '{$_POST['adress']}', `link` = '{$_POST['link']}' WHERE `id` = '{$_POST['id']}'";
}else{
$sql = "UPDATE `accommodation` SET `name` = '{$_POST['name']}', `description` = '{$_POST['description']}', `adress` = '{$_POST['adress']}', `link` = '{$_POST['link']}' WHERE `id` = '{$_POST['id']}'";
}
mysqli_query(get_connection(), $sql);
var_dump($sql);
// header("Location: admin.php?page=accommodation_list");
}