How do you add custom metadata to WooCommerce orders? Specifically a second external order ID

Question

I am working on building a custom integration from WooCommerce to our internal ERP. I hooked into the woocommerce_checkout_order_processed so that when an order is placed I send all relevant information to our ERP and the reply is an order ID. This is a different order ID than what is in WooCommerce and I need a way to map the ERP order ID to the WooCommerce order. What is the best way to accomplish this?

I have tried adding custom metadata, but so far that has failed. add_metadata( "shop_order", $order->id, "mapics_order", (string) $orderNumber, TRUE ); and am trying to avoid using wc_add_order_item_meta since this is not item specific, but for the entire order itself.

Answer 1

you can use woocommerce_checkout_update_order_meta hook to update order meta. Please check sample code

add_action('woocommerce_checkout_update_order_meta', 'custom_checkout_field_update_order_meta');

function custom_checkout_field_update_order_meta($order_id)
{
    session_start();
    if ($_SESSION['mapics_order'])
        update_post_meta($order_id, 'mapics_order', esc_attr(htmlspecialchars($_SESSION['mapics_order'])));
}