Bagaimana untuk melaksanakan sistem SKU produk dengan pelbagai spesifikasi dalam PHP

CREATE TABLE products (
    id INT(11) PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(100),
    description TEXT
);

CREATE TABLE attributes (
    id INT(11) PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(100),
    options TEXT
);

CREATE TABLE product_attributes (
    id INT(11) PRIMARY KEY AUTO_INCREMENT,
    product_id INT(11),
    attribute_id INT(11),
    option_id INT(11),
    sku VARCHAR(100),
    price DECIMAL(10, 2),
    stock INT(11),
    FOREIGN KEY (product_id) REFERENCES products(id),
    FOREIGN KEY (attribute_id) REFERENCES attributes(id)
);

function getAttributes($productId) {
    // 查询商品对应的规格选项
    $query = "SELECT a.id, a.name, a.options
              FROM attributes a
              INNER JOIN product_attributes pa ON a.id = pa.attribute_id
              WHERE pa.product_id = $productId";

    // 执行查询并返回结果
    $result = mysqli_query($conn, $query);
    $attributes = array();

    while ($row = mysqli_fetch_assoc($result)) {
        $optionIds = explode(',', $row['options']);
        $options = getOptions($optionIds);
        
        $attribute = array(
            'id' => $row['id'],
            'name' => $row['name'],
            'options' => $options
        );

        $attributes[] = $attribute;
    }

    return $attributes;
}

function getOptions($optionIds) {
    // 查询规格选项对应的数值
    $optionIds = implode(',', $optionIds);
    $query = "SELECT id, name, value
              FROM options
              WHERE id IN ($optionIds)";

    // 执行查询并返回结果
    $result = mysqli_query($conn, $query);
    $options = array();

    while ($row = mysqli_fetch_assoc($result)) {
        $option = array(
            'id' => $row['id'],
            'name' => $row['name'],
            'value' => $row['value']
        );

        $options[] = $option;
    }

    return $options;
}

function getSkus($productId) {
    // 查询商品对应的所有SKU
    $query = "SELECT sku, price, stock
              FROM product_attributes
              WHERE product_id = $productId";

    // 执行查询并返回结果
    $result = mysqli_query($conn, $query);
    $skus = array();

    while ($row = mysqli_fetch_assoc($result)) {
        $sku = array(
            'sku' => $row['sku'],
            'price' => $row['price'],
            'stock' => $row['stock']
        );

        $skus[] = $sku;
    }

    return $skus;
}