Wordpress crud frontend side

 Hello. Today I saw you how to create crud in user frontend side. 

Plugin Folder name : frontend-crud

Filename : frontend-crud.php

Code:-

<?php

/*

 * Plugin Name: Frontend CRUD

 * Description: Frontend crud functionality.

 * Version: 1.0

 * Author: Chirag

 * Plugin URI: #

 * Author URI: #

 */

register_activation_hook(__FILE__, 'table_creator');

function table_creator()

{

    global $wpdb;

    $charset_collate = $wpdb->get_charset_collate();

    $table_name = $wpdb->prefix . 'ems';

    $sql = "DROP TABLE IF EXISTS $table_name;

            CREATE TABLE $table_name(

            id mediumint(11) NOT NULL AUTO_INCREMENT,

            emp_id varchar(50) NOT NULL,

            emp_name varchar (250) NOT NULL,

            emp_email varchar (250) NOT NULL,

            emp_dept varchar (250) NOT NULL,

            PRIMARY KEY id(id)

            )$charset_collate;";

    require_once(ABSPATH . 'wp-admin/includes/upgrade.php');

    dbDelta($sql);

}

//[frontend_crud]

add_shortcode('frontend_crud','da_ems_frontend_crud_callback');

function da_ems_frontend_crud_callback(){

    global $wpdb;

    $table_name = $wpdb->prefix.'ems';

    $msg = '';

    if(@$_REQUEST['action'] == 'submit'){

        $wpdb->insert("$table_name", [

            'emp_id' => sanitize_text_field($_REQUEST['emp_id']),

            'emp_name'=> sanitize_text_field($_REQUEST['emp_name']),

            'emp_email'=> sanitize_email($_REQUEST['emp_email']),

            'emp_dept'=> sanitize_text_field($_REQUEST['emp_dept']),

        ]);

        if($wpdb->insert_id > 0){

            $msg = "Saved Successfully";

        }else{

            $msg = "Failed to save data";

        }

    }

    if(@$_REQUEST['action'] == 'update-emp' && @$_REQUEST['id']){

        $id = @$_REQUEST['id'];

        if(@$_REQUEST['emp_id'] && @$_REQUEST['emp_name'] && @$_REQUEST['emp_email'] && @$_REQUEST['emp_dept']){

            $update = $wpdb->update("$table_name",[

                'emp_id' =>sanitize_text_field($_REQUEST['emp_id']),

                'emp_name' =>sanitize_text_field($_REQUEST['emp_name']),

                'emp_email' =>sanitize_email($_REQUEST['emp_email']),

                'emp_dept' =>sanitize_text_field($_REQUEST['emp_dept'])],

                ['id' => $id]);

            if($update){

                $msg = "Data Updated <a href='".get_page_link(get_the_ID())."'>Add Employee</a>";

            }

        }

        $employee = $wpdb->get_row($wpdb->prepare("select * from $table_name where id = %d", $id), ARRAY_A);

        $emp_id = $employee['emp_id'];

        $emp_name = $employee['emp_name'];

        $emp_email = $employee['emp_email'];

        $emp_dept = $employee['emp_dept'];

    }

    if(@$_REQUEST['action'] == 'delete-emp' && @$_REQUEST['id']){

        $id = @$_REQUEST['id'];

        if($id){

            $row_exits = $wpdb->get_row($wpdb->prepare("select * from $table_name where id = %d",$id),ARRAY_A);

            if(count($row_exits)> 0){

                $wpdb->delete("$table_name", array('id'=>$id));

            }

        }

        ?>

            <script>

                location.href="<?php echo get_the_permalink(); ?>";

            </script>

        <?php

    }

    ?>

    <div class="form_container">

    <h4><?php echo @$msg; ?></h4>

    <form method="post">

        <p>

            <label>EMP ID</label>

            <input type="text" name="emp_id" value="<?php echo @$emp_id; ?>" placeholder="Enter ID" required>

        </p>

        <p>

            <label>Name</label>

            <input type="text" name="emp_name"  value="<?php echo @$emp_name; ?>" placeholder="Enter Name" required>

        </p>

        <p>

            <label>Email</label>

            <input type="email" name="emp_email" value="<?php echo @$emp_email; ?>" placeholder="Enter Email" required>

        </p>

        <p>

            <label>Department</label>

            <input type="text" name="emp_dept" value="<?php echo @$emp_dept; ?>" placeholder="Enter Department" required>

        </p>

        <p>

            <button type="submit" name="action" value="<?php echo (@$_REQUEST['action'] == 'update-emp')?'update-emp':'submit'; ?>"><?php echo (@$_REQUEST['action'] == 'update-emp')?'Update':'Submit'; ?></button>

        </p>

    </form>

    </div>

<?php

    $employee_list = $wpdb->get_results("SELECT * FROM $table_name", ARRAY_A);

    $i = 1;

    if($employee_list > 0 ){ ?>

        <div style="margin-top: 40px">

            <table border="1" cellpadding="10" style="font-size:14px;">

                <tr>

                <th>S. No.</th>

                <th>EMP ID</th>

                <th>Name</th>

                <th>Email</th>

                <th>Dept.</th>

                <th>Action</th>

                </tr>

                <?php foreach ($employee_list as $index =>  $employee):

                    ?>

                    <tr>

                        <td><?php echo $i++; ?></td>

                        <td><?php echo $employee['emp_id'];  ?></td>

                        <td><?php echo $employee['emp_name']; ?></td>

                        <td><?php echo $employee['emp_email'];; ?></td>

                        <td><?php echo $employee['emp_dept'];; ?></td>

                        <td>

                            <a href="?action=update-emp&id=<?php echo $employee['id']; ?>">Update</a>

                            <a href="?action=delete-emp&id=<?php echo $employee['id']; ?>" onclick="return confirm('Are you sure to remove this record?')">Delete</a>

                        </td>

                    </tr>

                <?php endforeach; ?>

            </table>

        </div>

    <?php }

}