将wordpress表单输入到sql中

I need a little help with my php script and getting it to function from Wordpress. I have installed a plugin that can run my php script. But when I input data into the fields and press submit, the form clears and nothing is added to the db. Where am I going wrong?

First with my HTML as followed:

<form method="post">
<table style="height: 149px;" width="220">
<tbody>
<tr>
<td style="width: 102px;">Medlemsnr:</td>
<td style="width: 102px;"><input name="stor_medlemsnr" type="smallint" />                
</td> 
</tr>
<tr>
<td style="width: 102px;">Navn:</td>
<td style="width: 102px;"><input name="stor_navn" type="text" /></td>
</tr>
<tr>
<td style="width: 102px;">Båd:</td>
<td style="width: 102px;"><input name="stor_baad" type="text" /></td>
</tr>
<tr>
<td style="width: 102px;">Dato:</td>
<td style="width: 102px;"><input name="stor_date" type="date" /></td>
</tr>
<tr>
<td style="width: 102px;">Art:</td>
<td style="width: 102px;"><input name="stor_art" type="text" /></td>
</tr>
<tr>
<td style="width: 102px;">Kg:</td>
<td style="width: 102px;"><input name="stor_kg" type="decimal(11,0)" /></td>
</tr>
</tbody>
</table>
<input type="Submit" />

[xyz-ips snippet="insert"]

The above "insert" calls the following php:

$servername = "localhost";
$username = "******dk_user";
$password = "********";
$dbname = "******dk_storfanger2017";

$con = mysql_connect(localhost,$username,$password);
if (!$con)
{
die('Could not connect: ' . mysql_error());
}

mysql_select_db( $dbname, $con);
$sql="INSERT INTO `******dk_storfanger2017`.`stor_2017` (`2017_medlemsnr`,                   
`2017_navn`, `2017_dato`, `2017_baad`, `2017_art`, `2017_kg`) 
VALUES($_POST[stor_medlemsnr],$_POST[stor_navn],$_POST[stor_baad],
$_POST[stor_date],$_POST[stor_art],$_POST[stor_kg])";

if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
echo "1 record added";

mysql_close($con)    

I hope somebody is able to point me in the right direction, getting this to work.

I also tried building it into insert.php, but wordpress will not accept the page, and gives me a HTTP 500 error when trying to access it.

I think $_POST['stor_kg'] is right thing not $_POST[stor_art] :

$sql="INSERT INTO `******dk_storfanger2017`.`stor_2017` (`2017_medlemsnr`,                   
    `2017_navn`, `2017_dato`, `2017_baad`, `2017_art`, `2017_kg`) 
    VALUES(". $_POST['stor_medlemsnr'] .",". $_POST['stor_navn'] .",".
    $_POST['stor_baad'] .",". $_POST['stor_date'] .",".
    $_POST['stor_art'] .",". $_POST['stor_kg'] .")" ;