<?php
add_action('admin_init', 'isetup_database_init', 200);
function isetup_database_init(){
    global $wpdb;
    $table = $wpdb->base_prefix . ISETUP_DATA['table_name'];

    $query = $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $table ) );

    if ( $wpdb->get_var( $query ) != $table ) { // Create table if not exist
        $charset_collate = $wpdb->get_charset_collate();
        $sql = "CREATE TABLE IF NOT EXISTS $table (
            id mediumint(9) NOT NULL AUTO_INCREMENT,
            page_id tinytext NULL,
            page_title tinytext NULL,
            page_parent tinytext NULL,
            author tinytext NULL,
            created_at tinytext NULL,
            PRIMARY KEY  (id)
        ) $charset_collate";
            require_once( ABSPATH .'wp-admin/includes/upgrade.php' );
            dbDelta( $sql );
    } else {
        wp_redirect(admin_url('/admin.php?page=' . ISETUP_DATA['inf_slug']));
    }
}