Replace URL in WordPress

code.php

<?php


add_action( 'admin_menu', 'atr_menu' );

function atr_menu() {
  add_options_page( 'ATR Plugin Options', 'ATR Convert', 'manage_options', 'atr-convert', 'atr_options' );
}

function atr_options() {
  if ( !current_user_can( 'manage_options' ) )  {
    wp_die( __( 'You do not have sufficient permissions to access this page.' ) );
  }
  
  if( isset( $_POST['option_save'] ) ){
    $options = $_POST;
    update_option( 'atr_options', $options );
    wp_redirect( admin_url( 'options-general.php?page=atr-convert&msg=Data+saved.' ) );
  }
  
  $options = get_option( 'atr_options', true );
  
  if( ! isset( $options ) || $options['newurl'] == '' )
    $options['options']['newurl'] = get_site_url();
  
  if( isset( $_REQUEST['replace_url'] ) && $_REQUEST['replace_url'] == 'now' ){
    global $wpdb;

    $db = "Tables_in_" . DB_NAME;
    $tables = $wpdb->get_results( 'SHOW TABLES' );
    foreach( $tables as $q ){
      $table = $q->$db;
      $cols = $wpdb->get_results( 'SHOW COLUMNS FROM ' . $table );
      
      $query = "UPDATE $table SET ";
      foreach( $cols as $col ){
        $query .= $col->Field . " = REPLACE({$col->Field}, '{$options['options']['oldurl']}/', '{$options['options']['newurl']}/'), ";
      }
      $query = rtrim( $query, ", " );
      $wpdb->query( $query );
    }
    wp_redirect( admin_url( 'options-general.php?page=atr-convert&msg=All+URLs+are+replaced.' ) );
  }
  ?>
  <div class="wrap">
    <?php if( isset( $_REQUEST['msg'] ) && $_REQUEST['msg'] != '' ) { ?>
    <div class="updated">
      <p>
        <?php echo str_replace( '+', ' ', $_REQUEST['msg'] ); ?>
      </p>
    </div>
    <?php } ?>
    <form action="<?php echo admin_url( 'options-general.php?page=atr-convert&noheader=true' ) ?>" method="post">
      <table cellpadding="5" cellspacing="5">
        <tr>
          <th>Old URL (without trailing slash)</th>
          <td><input type="text" name="options[oldurl]" value="<?php echo isset( $options['options']['oldurl'] ) && $options['options']['oldurl'] != '' ? $options['options']['oldurl'] : '' ?>"></td>
        </tr>
        <tr>
          <th>New URL (without trailing slash)</th>
          <td><input type="text" name="options[newurl]" value="<?php echo $options['options']['newurl'] ?>"></td>
        </tr>
      </table>
      <p><input type="submit" class="button button-primary" name="option_save" value="Save" style="width: 100px; text-align: center;"></p>
    </form>
    <p><a class="button button-primary" href="<?php echo admin_url( 'options-general.php?page=atr-convert&replace_url=now&noheader=true' ) ?>">Replace</a></p>
  </div>
  <?php
  
}