how to solve this undefined variable error in this code?
<pre><code>&lt;html&gt;

&lt;body&gt;
&lt;form action="upload.php" method="post"
enctype="multipart/form-data"&gt;
&lt;label for="file"&gt;Filename:&lt;/label&gt;
&lt;input type="file" name="file_field"&gt;&lt;br&gt;
&lt;input type="submit" name="submit" value="Submit"&gt;
&lt;/form&gt;

&lt;/body&gt;
&lt;/html&gt;
</code></pre>

<p>I get an error message as below:  </p>

<pre><code>Notice: Undefined variable: file_field in C:\xampp\htdocs\upload.php on line 113  
</code></pre>

<p>I tried defining <code>$file_field</code> on the top of the page but the problem with that is I don't get the file name in the MySQL database instead i get just <code>Array</code> and I also get the following error:  </p>

<pre><code>Notice: Array to string conversion in C:\xampp\htdocs\upload.php on line 114  
</code></pre>

<p>Has anyone any idea? Help.</p>

<pre><code>&lt;?php

function uploadFile ($file_field = null, $check_image = false, $random_name = false) {

//Config Section    
//Set file upload path
$path = 'c:/xampp/htdocs/images/'; //with trailing slash
//Set max file size in bytes
$max_size = 1000000;
//Set default file extension whitelist
$whitelist_ext = array('jpg','png','gif');
//Set default file type whitelist
$whitelist_type = array('image/jpeg', 'image/png','image/gif');

//The Validation
// Create an array to hold any output
$out = array('error'=&gt;null);

if (!$file_field) {
$out['error'][] = "Please specify a valid form field name";           
}

if (!$path) {
$out['error'][] = "Please specify a valid upload path";               
}

if (count($out['error'])&gt;0) {
return $out;
}

//Make sure that there is a file
if((!empty($_FILES[$file_field])) &amp;&amp; ($_FILES[$file_field]['error'] == 0)) {

// Get filename
$file_info = pathinfo($_FILES[$file_field]['name']);
$name = $file_info['filename'];
$ext = $file_info['extension'];

//Check file has the right extension           
if (!in_array($ext, $whitelist_ext)) {
$out['error'][] = "Invalid file Extension";
}

//Check that the file is of the right type
if (!in_array($_FILES[$file_field]["type"], $whitelist_type)) {
$out['error'][] = "Invalid file Type";
}

//Check that the file is not too big
if ($_FILES[$file_field]["size"] &gt; $max_size) {
$out['error'][] = "File is too big";
}

//If $check image is set as true
if ($check_image) {
if (!getimagesize($_FILES[$file_field]['tmp_name'])) {
$out['error'][] = "Uploaded file is not a valid image";
}
}

//Create full filename including path
if ($random_name) {
// Generate random filename
$tmp = str_replace(array('.',' '), array('',''), microtime());

if (!$tmp || $tmp == '') {
$out['error'][] = "File must have a name";
}     
$newname = $tmp.'.'.$ext;                                
} else {
$newname = $name.'.'.$ext;
}

//Check if file already exists on server
if (file_exists($path.$newname)) {
$out['error'][] = "A file with this name already exists";
}

if (count($out['error'])&gt;0) {
//The file has not correctly validated
return $out;
} 

if (move_uploaded_file($_FILES[$file_field]['tmp_name'], $path.$newname)) {
//Success
$out['filepath'] = $path;
$out['filename'] = $newname;
return $out;
} else {
$out['error'][] = "Server Error!";
}

} else {
$out['error'][] = "No file uploaded";
return $out;
}      
}
$con = mysql_connect("localhost","root","");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("simple_login", $con);

mysql_query("INSERT INTO photo (photo)
VALUES ('$file_field')");


mysql_close($con);
?&gt;
</code></pre>
