Create nested relationships in Laravel - php

Question

I've been trying to discover whether or not it's currently possible to do the following.
Basically I have three models: Customer, Invoice, and Unit. (Customer has one Invoice; an Invoice has many Units).
I was wondering if it was possible to seamlessly do the following:
...
# Let's pretend that further up the code that
# Customer has all the properties set and now
# being saved in the database.
$Customer->save();
# This is currently trying set the values of
# 'units' to a non-existent table column in
# 'invoices' table.
$Customer->invoice()->create([
"units" => [
[
"name" => "Unit 1",
"amount" => 999.99,
"tax" => "20%",
"type" => "+"
]
]
]);

Answer 1

If you setup the relationships in the model as you described them, then you can achieve it close to what you've shown. Something like this:
Customer
public function invoice()
{
return $this->hasOne(Invoice::class);
}
Invoice
public function units()
{
return $this->hasMany(Unit::class);
}
Then calling:
$customer->invoice()->units()->create([
"name" => "Unit 1",
"amount" => 999.99,
"tax" => "20%",
"type" => "+"
]);
Should work.

Answer 2

If you setup the relationships in the model as you described them, then you can achieve it close to what you've shown. Something like this:
Customer
public function invoice()
{
return $this->hasOne(Invoice::class);
}
Invoice
public function units()
{
return $this->hasMany(Unit::class);
}
Then calling:
$customer->invoice()->units()->create([
"name" => "Unit 1",
"amount" => 999.99,
"tax" => "20%",
"type" => "+"
]);
Should work.
if you call save on the invoice first, then you should just call $invoice->units()
$invoice = $customer->invoice()->create([
"campany" => "Unit 1",
"dat" => "2022-02-18"
]);
$invoice->units()->create([
"name" => "Unit 1",
"amount" => 999.99,
"tax" => "20%",
"type" => "+"
]);
... instead of doing it through the Customer. so $invoice = $customer->invoice()->create(...); before, and then add units.