Insert multiple check box values into multiple rows with different id

I have multiple rows containing multiple checkbox. I need values for every clicked checkbox in each row to be inserted in database. The rows have different ids. I have this code but don't know how to insert the data in their respective rows.

$check=$_POST['check'];

        if(isset($_POST['btnSubmit']))
        {
            if(!empty($check))
            {
                foreach($check as $val)
                {
                    mysql_query(" Update ojt_group3_pole set MER_CAB_ATT_EXIS_INV='$val'");
                }
            }
        }