// database/migrations/xxxx_create_orders_table.php
public function up()
{
    Schema::create('orders', function (Blueprint $table) {
        $table->id();
        $table->foreignId('user_id')->nullable()->constrained()->nullOnDelete();
        $table->string('order_number')->unique();
        $table->decimal('subtotal', 10, 2);
        $table->decimal('discount', 10, 2)->default(0);
        $table->decimal('shipping', 10, 2)->default(0);
        $table->decimal('total', 10, 2);
        $table->string('coupon_code')->nullable();
        $table->string('payment_method');
        $table->string('payment_status')->default('pending');
        $table->string('order_status')->default('pending');
        $table->text('shipping_address');
        $table->text('billing_address');
        $table->string('tracking_number')->nullable();
        $table->timestamps();
    });
}