PHP开发指南：实现完善的商品多规格SKU系统

class Product
{
    private $id;
    private $name;
    private $price;
    private $skus;

    // getters and setters
}

class Specification
{
    private $id;
    private $name;

    // getters and setters
}

class Attribute
{
    private $id;
    private $name;

    // getters and setters
}

class SKU
{
    private $id;
    private $product;
    private $specification;
    private $attribute;
    private $stock;

    // getters and setters
}

// 获取商品信息及SKU列表
public function getProduct($product_id)
{
    $product = Product::find($product_id);
    $skus = SKU::where('product_id', $product_id)->get();

    // 返回JSON数据
    return response()->json([
        'product' => $product,
        'skus' => $skus
    ]);
}

// 根据规格和属性获取SKU信息
public function getSKU($specification_id, $attribute_id)
{
    $sku = SKU::where('specification_id', $specification_id)
              ->where('attribute_id', $attribute_id)
              ->first();

    // 返回JSON数据
    return response()->json([
        'sku' => $sku
    ]);
}

// 更新SKU的库存数量
public function updateStock($sku_id, $stock)
{
    $sku = SKU::find($sku_id);
    $sku->stock = $stock;
    $sku->save();

    // 返回JSON数据
    return response()->json([
        'success' => true
    ]);
}