我目前正在使用PDO更新功能的项目上工作，更新功能工作正常，但我的问题是，当我尝试更新记录并保持原样时，当我看到数据库图像列为空……我如何检查文件是否为空，何时为空不更新?因为当我尝试用图像更新记录并点击更新按钮时，图像就消失了。
user.class.php
public function upload($id,$FILE_NAME,$FILE_SIZE,$FILE_TYPE,$username,$password,$province)
{
if(empty($_FILE['myImage']['name'])){
echo "error";
}
else
{
$stmt = $this->db->prepare("UPDATE tish_images SET FILE_NAME=:FILE_NAME,FILE_SIZE=:FILE_SIZE,FILE_TYPE=:FILE_TYPE,username=:username,password=:password,province=:province WHERE id=:id");
$errors= array();
foreach($_FILES['files']['tmp_name'] as $key => $error )
{
if ($error != UPLOAD_ERR_OK)
{
$errors[] = $_FILES['files']['name'][$key] . ' was not uploaded.';
//continue;
return FALSE;
}
$file_name = $key.$_FILES['files']['name'][$key];
$file_size = $_FILES['files']['size'][$key];
$file_tmp = $_FILES['files']['tmp_name'][$key];
$file_type = $_FILES['files']['type'][$key];
if($file_size > 2097152)
{
$errors[] = 'File size must be less than 2 MB';
//continue;
return FALSE;
}
try
{
$stmt->bindParam( ":id", $id);
$stmt->bindParam( ":FILE_NAME", $file_name, PDO::PARAM_STR );
$stmt->bindParam( ":FILE_SIZE", $file_size, PDO::PARAM_STR );
$stmt->bindParam( ":FILE_TYPE", $file_type, PDO::PARAM_STR );
$stmt->bindParam( ":username", $username);
$stmt->bindParam( ":password", $password);
$stmt->bindParam( ":province", $province);
$stmt->execute();
$desired_dir="image_uploads";
if(is_dir($desired_dir)==false)
{
mkdir($desired_dir, 0700);// Create directory if it does not exist
}
if(is_file($desired_dir.'/'.$file_name)==false)
{
move_uploaded_file($file_tmp,$desired_dir.'/'.$file_name);
return TRUE;
}
else
{ //rename the file if another one exist
$new_file=$desired_dir.'/'.$file_name.time();
move_uploaded_file($file_tmp,$new_file);
return TRUE;
}
}
catch(PDOException $e)
{
echo $e->getMessage();
return FALSE;
}
}
}
}
update.php
<?php
include_once 'DB.php';
$username = isset($_GET['username']) ? $_GET['username'] : '';
$password = isset($_GET['password']) ? $_GET['password'] : '';
$province = isset($_GET['province']) ? $_GET['province'] : '';
$FILE_NAME = isset($_GET['FILE_NAME']) ? $_GET['FILE_NAME'] : '';
$FILE_SIZE = isset($_GET['FILE_SIZE']) ? $_GET['FILE_SIZE'] : '';
$FILE_TYPE = isset($_GET['FILE_TYPE']) ? $_GET['FILE_TYPE'] : '';
if(isset($_FILES['files'])){
$id = $_GET['id'];
$username = $_POST['username'];
$password = $_POST['password'];
$province = $_POST['province'];
if($crud->upload($id,$FILE_NAME,$FILE_SIZE,$FILE_TYPE,$username,$password,$province))
{
echo "<script type='text/javascript'>alert('Successfully Updated!');</script>";
}
else
{
echo "<script type='text/javascript'>alert('Updating Failed!');</script>";
}
}
if(isset($_GET['id']))
{
$id = $_GET['id'];
extract($crud->getID($id));
}
?>
<?php echo $FILE_NAME; ?>
<br />
<br />
<input type="file" name="files[]" value="" multiple/>
<br />
<br />
<input type="text" name="username" value="<?php echo $username; ?>">
<br />
<br />
<input type="text" name="password" value="<?php echo $password ?>">
<br />
<br />
<input type="text" name="province" value="<?php echo $province ?>">
<br />
<input type="submit"/>
我假设您正在从<input type="file" />标记获取图像，并且您想检查是否选择了图像。您可以尝试使用empty()和$_FILE来检查是否选择了映像。
的例子:
<?php
if(empty($_FILE['myImage']['name'])):
//don't update and display an error message.
else:
//update record.
endif;
?>
*注意:如果你想只接受图像，你可以很容易地做到这一点与HTML <input type="file" name="imagefilename" accept="image/x-png, image/gif, image/jpeg" />。在插入新记录或将选定的文件上传到目录之前，不要忘记在PHP中验证这一点。