Morph relationship with composite key, is possible?

[underdpt]

Hello,

So, I have this relationship: an order line for a product belongs to an order, which has many delivery notes, which have many lines for that product (and this is a morphed relationship).

The key here is that the order line has two keys, the order id and the product id, and later on the relationship chain, I must filter by that product id, but on that point the relationship is a morphed one.

I've been able to get all the lines for the order from the order line, with this:

public function deliveryLines(): HasManyDeep
{
    return $this->hasManyDeep(
        DeliveryLines::class,
        [Order::class, Deliveries::class],
        [
            'id', 'orders_id', ['documento_type', 'documento_id'],
        ],
        ['orders_id']
    );
}

So, the question is... Can this be done?

Thanks!

[staudenmeir]

Hi @underdpt,
Please share the schema of all database tables that are involved in this relationship (you can remove the columns that aren't relevant to this question).

[underdpt]

Sure, thank you!

Here they are (ordered by the relationship order: order_lines -> orders -> delivery_notes -> delivery_notes_lines):

CREATE TABLE `order_lines` (
  `id` bigint UNSIGNED NOT NULL,
  `order_id` bigint UNSIGNED NOT NULL,
  `product_id` bigint UNSIGNED NOT NULL,
);

CREATE TABLE `orders` (
  `id` bigint UNSIGNED NOT NULL,
);

CREATE TABLE `delivery_notes` (
  `id` bigint UNSIGNED NOT NULL,
  `order_id` bigint UNSIGNED NOT NULL,
);

CREATE TABLE `delivery_notes_lines` (
  `id` bigint UNSIGNED NOT NULL,
  `product_id` bigint UNSIGNED NOT NULL,
  `documento_type` varchar(125) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `documento_id` bigint UNSIGNED DEFAULT NULL,
);

[staudenmeir]

Unfortunately, it's not possible to add the product_id constraint to the relationship. Composite keys can only be defined between "neighboring" tables.

You can add the constraint to the query when you use the relationships for lazy loading:

$orderLine = OrderLine::find($id);

$orderLine->deliveryLines()->where('product_id')->get();

This doesn't work with eager loading and I don't see a feasible way to make it work.

[underdpt]

Yes, that's what I though.

Thank you for taking a look!