What I want to do is to add a new record in table RECORD. This new record can be connected with multiple categories from table CATEGORY. Now, I have made the following code so I can select all categories that need to be connected with the records. However, I don’t know how I can post the selected categories into the RECORD table. So for example, if you have 5 categories in the CATEGORY table, named ‘one’, ‘two’, ‘three’, ‘four’ and ‘five’ (ID 1, 2, 3, 4, 5) and you select ‘one’ and ‘three’ to be added to the new record, it should be posted in the RECORD table into the column category_id with their ID ‘1, 3.

I already have a column ‘category_id’ in the table RECORD, but it does not add anything. I have the following code. Really hope someone can help me, I would appreciate it big time. I've searched quite a few questions but I still can't solve it :( Many thanks in advance!

record.php

<form method="post" action="<?php echo $home; ?>add_form.php">

        <div class="alert alert-info">
            <button type="button" class="close" data-dismiss="alert">&times;</button>
            <strong><i class="icon-user icon-large"></i>&nbsp;Test</strong>&nbsp;
        </div>

    <table width="400" border="0" cellspacing="1" cellpadding="2">
        <tr>
            <td width="100">Name</td>
            <td><input name="name" type="text" id="name"></td>
        </tr>
    </table>
<br />
    <table width="400" border="0" cellspacing="1" cellpadding="2">
        <tr>

            <table cellpadding="0" cellspacing="0" border="0">
                    <?php 
                    $query=mysql_query("select * from category")or die(mysql_error());
                    while($row=mysql_fetch_array($query)){
                        $id=$row['id'];
                    ?>
                    <tr>
                        <td width="22%"></td>
                        <td width="5%" style="padding-bottom: 4px"><input name="selector[]" type="checkbox" value="<?php echo $id; ?>"></td>
                        <td width="20%" style="padding-top:3px; padding-bottom: 1px"><?php echo $row['type'] ?></td>
                    </tr>
                    <?php  } ?>
            </table>

        </tr>
        <tr>
            <td><br /><br /></td>
        </tr>
    </table>

<input name="save" type="submit" id="save" class="btn btn-success" value="tEST">

</form>

add_form.php

<?php

require_once($_SERVER['DOCUMENT_ROOT'].'/dbconnect.php');

//specify here the Database name we are using
$name = $_POST['name'];
$category_id = isset($_POST['$id[$i]']) ? 1 : 0;

$sql = "INSERT INTO `test`.`record` (`id`, `name`, `category_id`, `date_added`) 
        VALUES (NULL, '{$name}', '{$category_id}', CURRENT_TIMESTAMP());";
//using mysql_query function. it returns a resource on true else False on error
$retval = mysql_query( $sql, $conn );    
if(! $retval )
{
  die('Could not enter data: ' . mysql_error());
}
?>
                    <script type="text/javascript">
                        alert("New Record is Added to the Database");
                        window.location = "record.php";
                    </script>
                    <?php
//close of connection
mysql_close($conn);
?>