仅将选定的复选框添加到数据库-PHP

I have the following form:

我有以下表格:

    <form action="done.php" method="POST">
<!-- This hidden check box is used to check if submit is clicked.-->
 <input type="hidden" name="check_submit" value="1" />
 <!--All the applications are added to an array which we can then use in done.php-->
<applications><h2>Applications</h2><br><table border="0" cellspacing="10" cellpadding="10">
<tr>
    <td><b>Application</b></td>
    <td><b>UK</b></td>
    <td><b>Spain</b></td>
    <td><b>France</b></td>
    <td><b>Benelux</b></td>
    <td><b>Germany</b></td>
    <td><b>Sweeden</b></td>
</tr>
<tr>
    <td>hey</td>
    <td><center><input type = "checkbox" name="hey[]" value ="heyuk"/></center></td>
        <td><center><input type = "checkbox" name="hey[]" value ="heyspain"/></center></td>
            <td><center><input type = "checkbox" name="hey[]" value ="heyfrance"/></center></td>
                <td><center><input type = "checkbox" name="hey[]" value ="heybenelux"/></center></td>
                    <td><center><input type = "checkbox" name="hey[]" value ="heygermany"/></center></td>
                        <td><center><input type = "checkbox" name="hey[]" value ="heysweeden"/></center></td>
</tr>
    <for