使用PHP和MySQL创建成员配置文件页面

我正在开发一个数据库驱动的网站，该网站有常规用户页面、成员页面和管理员页面。除了会员个人资料页面外，一切都很好。我无法使它正常工作。每次我更改某个内容时，它都会停止打印正确的内容，或者陷入困境，无法将其添加到数据库中。

这是我的代码：

 <?php if(!isset($_SESSION['level']) || $_SESSION['level'] != 'Member') :?>
                    <div id="mainMemberProfile">
                        <table>
            <form method='post' action='profile.php' name='profileform' id='profileform'>
                <tr>
                    <td>
                        <p>
                            <label for='firstname'>First Name:</label><br/>
                        </p>
                </td>
                    <td>
                        <p>
                            <input type='text' name='firstname' required value="<?php echo(isset($firstname['firstname'])); ?>"/>
                        </p>
                     </td>
                 </tr>
             <tr>
                 <td>
                        <p>
                            <label for='lastname'>Last Name:</label><br/>
                        </p></td>
                    <td><p>
                            <input type='text' name='lastname' required value="<?php echo(isset($lastname['lastname'])); ?>"/>
                    </p></td>
                 </tr>
                 <tr>
                    <td>
                        <p>
                        <label for='email'>Email:</label><br/>
                        </p></td>
                    <td><p>
                            <input type='text' name='email' required value="<?php echo(isset($email['email'])); ?>"/>
                        </p></td>
                 </tr>
                  <tr>
                     <td>
                        <p>
                            <label for='address'>Address:</label><br/>
                        </p></td>
                      <td><p>
                        <input type='text' name='address' required value="<?php echo(isset($address['address'])); ?>"/>
                        </p></td>
                 </tr>
                 <tr>
                    <td>
                        <p>
                            <label for='address2'>Address 2:</label><br/>
                        </p></td>
                     <td><p>
                        <input type='text' name='address2' value="<?php echo(isset($address2['address2'])); ?>"/>
                        </p></td>
                 </tr>
                 <tr>
                    <td>
                        <p>
                            <label for='city'>City:</label><br/>
                        </p></td>
                    <td><p>
                            <input type="text" name="city" required value="<?php echo(isset($city['city'])); ?>"/>
                        </p></td>
                 </tr>
              <tr>

                      <td><p>
                        <?php echo get_state(); ?>
                        </p></td>
                  </tr>
                  <tr>
                    <td>
                        <p>
                            <label for='zip'>Zip:</label><br/>
                    </p></td>
                    <td><p>
                            <input type='zip' name='zip' required value="<?php echo (isset($zip['zip'])); ?>"/>
                        </p></td>
                  </tr>
                  <tr>
                    <td>
                        <p>
                            <label for='residence'>Residence - Y or N:</label><br/>
                        </p></td>
                       <td><p>
                            <input type='residence' name='residence' required value="<?php echo (isset($residence['residence'])); ?>"/>
                        </p></td>
                 </tr>
                  <tr>
                    <td>
                        <p>
                            <label for='business'>Business - Y or N:</label><br/>
                        </p></td>
                      <td><p>
                            <input type='business' name='business' required value="<?php echo (isset($business['business'])); ?>"/>
                        </p></td>
                  </tr>
                   <tr>
                      <td><p>
                            <input type="submit" name="action" value="Submit"/>
                        </p></td>
                </tr>
              </form>
           </table>
 </div> </div>  
    <?php else :?>
 <div id="profilesession">
  <?php
 if (isset($_POST['firstname'])){
 $_SESSION['firstname'] = $_POST['firstname'];
 $firstname = $_SESSION['firstname'];}
 if (isset($_POST['lastname'])){
 $_SESSION['lastname'] = $_POST['lastname'];
 $lastname = $_SESSION['lastname'];}
 if (isset($_POST['email'])){
  $_SESSION['email'] = $_POST['email'];
  $email = $_SESSION['email'];}
 if (isset($_POST['address'])){
 $_SESSION['address'] = $_POST['address'];
 $address = $_SESSION['address'];}
 if (isset($_POST['address2'])){
 $_SESSION['address2'] = $_POST['address2'];
 $address2 = $_SESSION['address2'];}
 if (isset($_POST['city'])){
 $_SESSION['city'] = $_POST['city'];
 $city = $_SESSION['city'];}
 if (isset($_POST['state'])){
 $_SESSION['state'] = $_POST['state'];
 $state = $_SESSION['state'];}
 if (isset($_POST['zip'])){
 $_SESSION['zip'] = $_POST['zip'];
  $zip = $_SESSION['zip'];}
 if (isset($_POST['residence'])){
 $_SESSION['residence'] = $_POST['residence'];
 $residence = $_SESSION['residence'];}
 if (isset($_POST['business'])){
  $_SESSION['business'] = $_POST['business'];
  $business = $_SESSION['business'];}
 echo print_member_profile($firstname, $lastname, $email, $address, $address2, $city, $state, $zip, $residence, $business); ?>
                </div>
 <?php
$idaddresses = '';
 $idmembers = '';//get_members();''
$email = $_POST['email'];
 $lastname = $_POST["lastname"];
 $firstname = $_POST["firstname"];
 $address = $_POST['address'];
 $address2 = $_POST['address2'];
$city = $_POST['city'];
 $state = $_POST['state'];
$zip = $_POST['zip'];
$residence = $_POST['residence'];
 $business = $_POST['business'];
$idmembers = '';
 $lastname = isset($_POST['lastname']) ? $_POST['lastname'] : '';
 $firstname = isset($_POST['firstname']) ? $_POST['firstname'] : '';
 function get_member_ids($lastname, $firstname) {
  global $db;
     $query = $db->prepare("SELECT idmembers FROM members WHERE last = '$lastname' AND first = '$firstname'");
     $query->execute();
    $idmembers = $query->fetch()['idmembers'];
     return $idmembers;
 }
 function add_address($idaddresses, $idmembers, $email, $address, $address2, $city, $state, $zip, $residence, $business) {
    global $db;
    $lastname = isset($_POST['lastname']) ? $_POST['lastname'] : '';
$firstname = isset($_POST['firstname']) ? $_POST['firstname'] : '';
$email = isset($_POST['email']) ? $_POST['email'] : '';
 $address = isset($_POST['address']) ? $_POST['address'] : '';
$address2 = isset($_POST['address2']) ? $_POST['address2'] : '';
$city = isset($_POST['city']) ? $_POST['city'] : '';
$state = isset($_POST['state']) ? $_POST['state'] : '';
$zip = isset($_POST['zip']) ? $_POST['zip'] : '';
 $residence = isset($_POST['residence']) ? $_POST['residence'] : '';
 $business = isset($_POST['business']) ? $_POST['business'] : '';     $idmembers = get_member_ids($lastname, $firstname);
     $query = "INSERT INTO addresses
                  (idaddresses, idmembers, email, address, address2, city, state, zip, residence, business)
               VALUES
                  ('$idaddresses', '$idmembers', '$email', '$address', '$address2', '$city', '$state', '$zip', '$residence', '$business')";
   // var_dump($query);
    // var_dump($db); 
    $db->exec($query);
 }

   add_address($idaddresses, $idmembers, $email, $address, $address2, $city, $state, $zip, $residence, $business);

 ?> <?php endif;?>