Custom WP review plugin

<?php

function calculate_average($arr) {
    $count = count($arr); //total numbers in array
    foreach ($arr as $value) {
        $total = $total + $value; // total value of array numbers
    }
    $average = ($total/$count); // get average value
    return $average;
}

function show_review_shortcode($atts) {
   extract(shortcode_atts(array("id" => ''), $atts));

        $user = "root";
        $pass = "";
        $host = "localhost";
        $dbname = "dbname";
        mysql_connect("$host", "$user", "$pass") or die(mysql_error());
        mysql_select_db("$dbname") or die(mysql_error());
        $result = mysql_query("SELECT * FROM `reviews` WHERE `id` = $id");
                if (!$rec = @mysql_fetch_array($result)){
                    echo("Invalid Review.<br />");
                }else{
                    $brand = $rec['brand'];
                    $name = $rec['name'];
                    $eff = $rec['eff'];
                    $val = $rec['val'];
                    $ov = $rec['ov'];
                    $pro1 = $rec['pro1'];
                    $pro2 = $rec['pro2'];
                    $pro3 = $rec['pro3'];
                    $con1 = $rec['con1'];
                    $con2 = $rec['con2'];
                    $con3 = $rec['con3'];
                    $review = $rec['review'];
                    $reviewer_name = $rec['reviewer_name'];
                    $reviewer_email = $rec['email'];
                    $site = $rec['site'];

?>
<p><strong><?php echo $brand; ?> <?php echo $name; ?> Review<br /></strong></p>
<table width="500" border="1" cellspacing="0" cellpadding="0">
  <tbody>
    <tr>
      <td width="50%" height="116"><p><strong>Ratings:</strong><strong> </strong></p>
        <strong>Taste [Rating:2/5]</strong>:  [Rating:<?php echo $ov; ?>/5]<br />
          <strong>Effectiveness</strong>: [Rating:<?php echo $eff; ?>/5]<br />
          <strong>Value</strong>: [Rating:<?php echo $val; ?>/5]<br />
          <?php
                $overall_array = array($ov,$eff,$val);
                $overall_value = calculate_average($overall_array);
                $overall_value_formatted = number_format($overall_value, 2, '.', '');
            ?>
          <strong>Overall</strong>: [Rating:<?php echo $overall_value_formatted ?>/5]
        </td>
      <td width="50%"><div align="center"><strong> <a href="http://supplementjudge.net/out.php?id="><img src="http://www.supplementjudge.net/buy.png" width="180" height="71" border="0"></a></strong></div></td>
    </tr>
  </tbody>
</table>
<p><strong>Summary</strong></p>
<table width="500" border="1" cellspacing="0" cellpadding="0">
    <tbody>
        <tr>
        <td width="50%"><strong>Pros</strong></p>
            <ul>
                <li><?php echo $pro1; ?></li>
                <li><?php echo $pro2; ?></li>
                <li><?php echo $pro3; ?></li>
            </ul>
        </td>
        <td width="50%"><strong>Cons</strong></p>
        <ul>
          <li><?php echo $con1; ?></li>
          <li><?php echo $con2; ?></li>
          <li><?php echo $con3; ?></li>
        </ul>
        </td>
        </tr>
    </tbody>
</table>
<p><strong>My Review</strong></p>
<p><?php echo $review; ?></p>
<p><strong>Nutritional Information</strong></p>
<p>Bla</p>
<p><strong>Ingredients</strong></p>
<p>Bla</p>
[toggle title="Serving Info"]Bla[/toggle]
<?php
if (!empty($reviewer_name)){
echo "<p>Reviewed by: $reviewer_name</p>";
}
}
}
add_shortcode('review', 'show_review_shortcode');
?>