title: WP header reload
body: <p>I am new to wordpress plugin development. I made some coding and understand enough about making the menu -- sub-menu etc. In one sub-menu page I made a form that changes the email id in one of mytable in database. But to stop data inserting on page reload/refresh/page-back I have to give a header function but I am unable to do the same.</p>
  
  <p>In more simple words I just want to stop wordpress plugin to inserting/update data in table on page refresh. Please read my coding below.</p>
  
  <pre><code>&lt;form method="post" enctype="multipart/form-data"&gt;
      &lt;label&gt;&lt;b&gt;Mention Your Email Here :&lt;/b&gt;&lt;/label&gt;
      &lt;input type="email" name="email" id="email" placeholder="Enter your email here"/&gt;&lt;br/&gt;&lt;br/&gt;
      &lt;input type="submit" name="set" id="set" value="CHANGE"/&gt;
  &lt;/form&gt;
  
  &lt;br/&gt;&lt;br/&gt;
  
  &lt;u&gt;NOTE&lt;/u&gt; :&lt;br/&gt;
  1. Please write your email id in the field given above. This email id will be used to get emails of visitors contact query.
  &lt;br/&gt;
  2. Copy the shortcode given below to show the form on the website.&lt;br/&gt;
  &amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;b&gt;[myplugin]&lt;/b&gt;
  
  &lt;?php
  
  //getting the form email id value
  
  if (isset($_POST['set']) &amp;&amp; !empty($_POST['email'])) {
      $email = $_POST['email'];
      global $wpdb;
      $table_name = $wpdb-&gt;prefix . "myemail";
      $result = $wpdb-&gt;update($table_name, array('id' =&gt; '1', 'email' =&gt; $email), array('id' =&gt; '1'));
  
      if ($result &gt; 0) {
          echo "&lt;script&gt;alert('Successfully Updated');&lt;/script&gt;";
      } else {
          exit(var_dump($wpdb-&gt;last_query));
      }
  
      $wpdb-&gt;flush();
  } else {
      header('location: ------?????--------------');
  }
  
  ?&gt;
  </code></pre>
  
  <p>In header what should I write so the page comes to same page after reload. But without inserting/updating data.</p>