CRUD operation using $wpdb

What is $wpdb?

• In WordPress, $wpdb is a global object of the built-in wpdb class.
• It is automatically loaded and connected to your WordPress database (MySQL/MariaDB).
• It allows developers to interact with the database safely using methods for CRUD operations (Create, Read, Update, Delete).

The recommended way to access $wpdb in your WordPress PHP code is to declare $wpdb as a global variable using the global keyword, like this:

crate table in database

function akal_degree_college_student_table_direct() {
global $wpdb;(global object )
$table_name = $wpdb->prefix . “students”; // wp_students in database
$charset_collate = $wpdb->get_charset_collate();

$sql = "CREATE TABLE IF NOT EXISTS $table_name (
    id mediumint(9) NOT NULL AUTO_INCREMENT,
    firstname varchar(100) NOT NULL,
    lastname varchar(100) NOT NULL,
    class varchar(50) NOT NULL,
    roll_number varchar(50) NOT NULL,
    email varchar(100) NOT NULL,
    phone varchar(20) NOT NULL,
    created_at datetime DEFAULT CURRENT_TIMESTAMP NOT NULL,
    PRIMARY KEY  (id),
    UNIQUE KEY roll_number (roll_number)
) $charset_collate;";

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

}
// run on theme activation (not every request)
add_action(‘after_switch_theme’, ‘akal_degree_college_student_table_direct’);