How to store check box values (0 or 1) in Database in Codeignitor

Hello I need help in check box, i want store 0 or 1 in Database,if checkbox will check then otherwise 0,i tried in hidden value, its working, but checkbox is in loop so it did not get proper output. so how to implement it give me some hint.

Here is My View:

">

                        <label>Select User</label>

                        <select name="user_role" id="user_role" onchange="calculate(this)">

                            <option>--Select User--</option>  

                            <?php
                            foreach ($roll_get as $roll) {
                                ?>
                                <option value="<?php echo $roll->user_id; ?>" id="<?php echo $roll->user_id; ?>"><?php echo $roll->full_name; ?></option>
                                <?php
                            }
                            ?>
                        </select><br>
                        <input id="checkAll" type="button" value="Check All">
                        <div class="button">

                            <?php
                            foreach ($listMenuLevel1 as $menu1) {
                                ?>

                                <div id="checkboxlist">

                                    <li class="treeview">

                                        <input type="hidden" name="sample[]" value="0"> 
                                        <input type="checkbox" name="sample[]" value="1"> 

                                        <span><?php echo $menu1->category_name; ?></span> 
                                        </a>
                                        <?php if (count($this->main_model->listchildMenus($menu1->category_id)) > 0) { ?>
                                            <ul class="treeview-menu">
                                                <?php foreach ($this->main_model->listchildMenus($menu1->category_id) as $menu2) { ?>
                                                    <li ><input type="checkbox" name="sample[]" value="" /><a href="<?php echo base_url(); ?><?php echo $menu2->category_link; ?>"><?php echo $menu2->category_name; ?></a></li>
                                                    <ul>
                                                        <?php foreach ($this->main_model->listchildMenus($menu2->category_id) as $menu3) { ?>
                                                            <li><input type="checkbox" name="sample[]"value="" /><a href="<?php echo base_url(); ?><?php echo $menu3->category_link; ?>"><?php echo $menu3->category_name; ?></a></li>
                                                        <?php } ?> 
                                                    </ul>


                                                <?php } ?>
                                            </ul>
                                        <?php } ?>

                                    </li>
                                </div>
                                <?php
                            }
                            ?> 



                            <input type="submit" class="btn btn-primary" value="Save">
                            </form>