在Laravel中，从一个表到另一个表中的同一字段的多个外键

CREATE TABLE customers (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(255) NOT NULL
);

CREATE TABLE orders (
    id INT PRIMARY KEY AUTO_INCREMENT,
    customer_id INT,
    amount DECIMAL(10, 2),
    FOREIGN KEY (customer_id) REFERENCES customers(id)
);

CREATE TABLE payments (
    id INT PRIMARY KEY AUTO_INCREMENT,
    customer_id INT,
    amount DECIMAL(10, 2),
    FOREIGN KEY (customer_id) REFERENCES customers(id)
);

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Customer extends Model
{
    public function orders()
    {
        return $this->hasMany(Order::class);
    }

    public function payments()
    {
        return $this->hasMany(Payment::class);
    }
}

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Order extends Model
{
    public function customer()
    {
        return $this->belongsTo(Customer::class);
    }
}

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Payment extends Model
{
    public function customer()
    {
        return $this->belongsTo(Customer::class);
    }
}

use Illuminate\Support\Facades\DB;

DB::transaction(function () {
    $customer = Customer::find($customerId);
    if ($customer) {
        $order = new Order(['amount' => $amount]);
        $customer->orders()->save($order);
    } else {
        throw new \Exception('Customer not found');
    }
});