Crud operation in wordpress custom plugin

What is a CRUD system, how to integrate a CRUD system for MySQL in your WordPress site, and what are the pros and cons of using different approaches?

We are dealing with crud database operations so we need to have database table to store be able to store data.

Create Table

register_activation_hook( __FILE__, 'crudOperationsTable');

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,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);
     }
   }

insert form (crud.php page name suppose)

<form action="" method="post">
   <input type="text" id="name" name="name">
   <input type="text" id="email" name="email">
   <button id="newsubmit" name="submit" type="submit">INSERT</button>
</form>

insert query

if (isset($_POST['submit'])) {   
   $name = $_POST['name'];
   $email = $_POST['email'];

   $wpdb->query("INSERT INTO $table_name(name,email) 
          VALUES('$name','$email')");
   echo "<script>location.replace('admin.php?page=crud.php');</script>";
}

OR

$welcome_name = 'Mr. WordPress';
$welcome_text = 'Congratulations, you just completed the installation!';

$table_name = $wpdb->prefix . 'student';
$wpdb->insert( 
  $table_name, 
  array( 
    'time' => current_time( 'mysql' ), 
    'name' => $welcome_name, 
    'address' => $welcome_text,
    'roll_no' => 10 
  ) 

);

fetch data 

<?php  
 
   $result = $wpdb->get_results("SELECT * FROM $table_name");
   foreach ($result as $print) {
     echo "<tr>
           <td width='25%'>$print->user_id</td>
           <td width='25%'>$print->name</td>
           <td width='25%'>$print->email</td>
           <td width='25%'><a href='admin.php?page=crud.php&upt=$print->user_id'>
               <button type='button'>Edit</button></a> 
               <a href='admin.php?page=crud.php&del=$print->user_id'>
               <button type='button'>DELETE</button></a>
           </td>
    </tr>";
}

?>

edit form 

<?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 "<table class='wp-list-table widefat striped'>
        <thead><tr>
           <th width='25%'>User ID</th><th width='25%'>Name</th>
           <th width='25%'>Email Address</th>
           <th width='25%'>Actions</th>
         </tr>
        </thead>
     <tbody>

  <form action='' method='post'>
     <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%'><button id='uptsubmit' name='uptsubmit' type='submit'>UPDATE</button> 
          <a href='admin.php?page=crud.php'><button type='button'>CANCEL</button></a>
       </td>
     </tr>
   </form>
</tbody>
</table>";

}

?>

update query 

if (isset($_POST['uptsubmit'])) {  
   $id = $_POST['uptid'];
   $name = $_POST['uptname'];
   $email = $_POST['uptemail'];
   
   $wpdb->query("UPDATE $table_name SET name='$name',
     email='$email' WHERE user_id='$id'");

   echo "<script>location.replace('admin.php?page=crud.php');</script>";

}

delete query 

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.php');</script>";
}