Wordpress Simple Crud Plugin Create

     <?php
    /*
    Plugin Name: CRUD Operations
    Plugin URI:     Description: A simple plugin that allows you to perform Create (INSERT), Read (SELECT), Update and Delete operations.
    Version: 1.0.0
    Author:     Author URI:     License: GPL2
    */
    register_activation_hook( __FILE__, 'crudOperationsTable');
    
    define( 'CRUD__PLUGIN_DIR', plugin_dir_path( __FILE__ ) );
    
    function crudOperationsTable() {
      global $wpdb;
      $charset_collate = $wpdb->get_charset_collate();
      $table_name = $wpdb->prefix . 'userstable';
      $sql = "CREATE TABLE `$table_name` (
      `user_id` int(11) NOT NULL AUTO_INCREMENT,
      `name` varchar(220) DEFAULT NULL,
      `email` varchar(220) DEFAULT NULL,
      `image` varchar(220) DEFAULT NULL,
      PRIMARY KEY(user_id)
      ) ENGINE=MyISAM DEFAULT CHARSET=latin1;
      ";
      if ($wpdb->get_var("SHOW TABLES LIKE '$table_name'") != $table_name) {
        require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
        dbDelta($sql);
      }
    }
    add_action('admin_menu', 'addAdminPageContent');
    function addAdminPageContent() {
      add_menu_page('CRUD', 'CRUD', 'manage_options' ,__FILE__, 'crudAdminPage', 'dashicons-wordpress');
    }
    function crudAdminPage() {
      global $wpdb;
      $table_name = $wpdb->prefix . 'userstable';
      if (isset($_POST['newsubmit'])) {
        $name = $_POST['newname'];
        $email = $_POST['newemail'];
        $target_dir = CRUD__PLUGIN_DIR."img/";
        $target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
        $uploadOk = 1;
        $imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);
            //$new_filename = $target_dir . uniqid() . '.' . $imageFileType;
            $new_filename = uniqid() . '.' . $imageFileType;
            if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $new_filename))
                        {   
                            $filee = $new_filename;
                        }
        $wpdb->query("INSERT INTO $table_name(name,email, image) VALUES('$name','$email','$filee')");
        //echo "<script>location.replace('admin.php?page=crud.php');</script>";
        echo "<script>location.replace('admin.php?page=crud-operations/crud-operations.php');</script>";
      }
      if (isset($_POST['uptsubmit'])) {
        $id = $_POST['uptid'];
        $name = $_POST['uptname'];
        $email = $_POST['uptemail'];
        $target_dir = CRUD__PLUGIN_DIR."img/";
        $target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
        $uploadOk = 1;
        $imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);
            //$new_filename = $target_dir . uniqid() . '.' . $imageFileType;
            $new_filename = uniqid() . '.' . $imageFileType;
            if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $new_filename))
                        {   
                            $filee = $new_filename;
                        }
        $wpdb->query("UPDATE $table_name SET name='$name',email='$email',image='$filee' WHERE user_id='$id'");
        //echo "<script>location.replace('admin.php?page=crud.php');</script>";
        echo "<script>location.replace('admin.php?page=crud-operations/crud-operations.php');</script>";
      }
      if (isset($_GET['del'])) {
        $del_id = $_GET['del'];
        $wpdb->query("DELETE FROM $table_name WHERE user_id='$del_id'");
        echo "<script>location.replace('admin.php?page=crud-operations/crud-operations.php');</script>";
      }
     if (!isset($_GET['upt'])) {
      ?>
      <div class="wrap">
        <h2>CRUD Operations</h2>
        <table class="wp-list-table widefat striped">
          <thead>
            <tr>
              <th>User ID</th>
              <th>UserName</th>
              <th>Email Address</th>
              <th>Actions</th>
            </tr>
          </thead>
          <tbody>
            <form action="" method="post" enctype='multipart/form-data'>
              <tr>
                <td><input type="text" value="AUTO_GENERATED" disabled></td>
                <td><input type="text" id="newname" name="newname"></td>
                <td><input type="text" id="newemail" name="newemail"></td>
                <td><input type="file" id="fileToUpload" name="fileToUpload"></td>
                <td><button id="newsubmit" name="newsubmit" type="submit">INSERT</button></td>
              </tr>
            </form>
            <?php
              $result = $wpdb->get_results("SELECT * FROM $table_name");
              foreach ($result as $print) {
                echo "
                  <tr>
                    <td>$print->user_id</td>
                    <td>$print->name</td>
                    <td>$print->email</td>
                    <td><img style='width: 150px' src=".$print->image."></td>
                    <td><a href='admin.php?page=crud-operations/crud-operations.php&upt=$print->user_id'><button type='button'>UPDATE</button></a> <a href='admin.php?page=crud-operations/crud-operations.php&del=$print->user_id'><button type='button'>DELETE</button></a></td>
                  </tr>
                ";
              }
            ?>
          </tbody>  
        </table>
        <br>
        <br>
        <?php
    }
        
          if (isset($_GET['upt'])) {
            $upt_id = $_GET['upt'];
            $result = $wpdb->get_results("SELECT * FROM $table_name WHERE user_id='$upt_id'");
            foreach($result as $print) {
              $name = $print->name;
              $email = $print->email;
            }
            echo "<br><br>
            <table class='wp-list-table widefat striped'>
              <thead>
                <tr>
                  <th width='25%'>User ID</th>
                  <th width='25%'>UserName</th>
                  <th width='25%'>Email Address</th>
                  <th width='25%'>Actions</th>
                </tr>
              </thead>
              <tbody>
                <form action='' method='post' enctype='multipart/form-data'>
                  <tr>
                    <td width='25%'>$print->user_id <input type='hidden' id='uptid' name='uptid' value='$print->user_id'></td>
                    <td width='25%'><input type='text' id='uptname' name='uptname' value='$print->name'></td>
                    <td width='25%'><input type='text' id='uptemail' name='uptemail' value='$print->email'></td>
                    <td width='25%'><input type='file' id='fileToUpload' name='fileToUpload'><br><img style='width: 200px' src=".$print->image."></td>
                    <td width='25%'><button id='uptsubmit' name='uptsubmit' type='submit'>UPDATE</button> <a href='admin.php?page=crud-operations/crud-operations.php'><button type='button'>CANCEL</button></a></td>
                  </tr>
                </form>
              </tbody>
            </table>";
          }
        ?>
      </div>
      <?php
    }