Laravel not setting the provided foreignID - laravel

Question

I am currently trying to save a customer and using a hasMany Eloquent-Relationship to store addresses with it in a seperate table. Now i ran into the problem, that laravel is storing every value right in both tables except the foreignID. Here are some code snippets which I am using. The request returns to success, although the supplier_id (foreignKey) in the supplier_addresses table is not set.
Supplier Migration:
Schema::create('suppliers', function (Blueprint $table) {
$table->string('supplier_id')->primary();
$table->string('supplierName');
$table->string('taxNumber');
$table->timestamps();
});
SupplierAddresses Migration:
Schema::create('supplier_addresses', function (Blueprint $table) {
$table->id();
$table->string('supplier_id');
$table->string('street');
$table->string('houseNumber');
$table->string('stairway')->nullable();
$table->string('floor')->nullable();
$table->string('door')->nullable();
$table->string('zipCode');
$table->string('city');
$table->string('type');
$table->timestamps();
});
Supplier Model:
class Supplier extends Model
{
use HasFactory;
protected $primaryKey = 'supplier_id';
protected $keyType = 'string';
public $incrementing = 'false';
protected $guarded = [];
protected $fillable = [
'supplier_id',
'supplierName',
'taxNumber'
];
public function address() {
return $this->hasMany(SupplierAddress::class, "supplier_id");
}
}
SupplierAddresses Model:
class SupplierAddress extends Model
{
use HasFactory;
protected $fillable = [
'street',
'houseNumber',
'stairway',
'floor',
'door',
'zipCode',
'city',
'type',
'supplier_id'
];
}
Suppliers Controller:
class SuppliersController extends Controller
{
public function show() {
return view('addSupplier');
}
public function submit() {
request()->validate([
'supplier_id' => 'required',
'supplierName' => 'required',
'taxNumber' => 'required'
]);
$supplier = Supplier::create([
'supplier_id' => request('supplier_id'),
'supplierName' => request('supplierName'),
'taxNumber' => request('taxNumber')
]);
$supplier->address()->create([
'supplier_id' => request('supplier_id'),
'street' => request('street'),
'houseNumber' => request('houseNumber'),
'stairway' => request('stairway'),
'floor' => request('floor'),
'door' => request('door'),
'zipCode' => request('zipCode'),
'city' => request('city'),
'type' => 'P'
]);
return redirect()->back()->with('success', 'Das Anlegen eines neuen Lieferanten war erfolgreich.');
}
}
Suppliers Table:
SupplierAddresses Table:

Answer 1

You need to assign foreign key constrained between suppliers and supplier_addresses table
example
primary key
Schema::create('suppliers', function (Blueprint $table) {
$table->id();
$table->string('supplier_id');
$table->timestamps();
});
foregin key
Schema::table('supplier_addresses', function (Blueprint $table) {
$table->unsignedBigInteger('supplier_id');
$table->foreign('supplier_id')->references('id')->on('suppliers');
});
Or
Schema::table('supplier_addresses', function (Blueprint $table) {
$table->foreignId('supplier_id')->constrained('suppliers');
});
for more details you can see this https://laravel.com/docs/9.x/migrations#foreign-key-constraints