深层关系，*child* 关系取决于 *great-grandparent* id - with |加载 - Laravel/Eloquent

Question

我有这个数据库/模型结构（示例）：

*食物类别 ------------ (id, name) - *不相关

食物 ---------------------- (id, food_category_id, name, ...)

配件组 ---------（id、name、...）

Foods_Accessory Groups - (food_id, acc_group_id) - 数据透视表

附件 ---------------- (id, acc_group_id, name, ...)

Foods_Accessories_Prices -（food_id、accessories_id、price） - 数据透视表

模型

• FoodCategory (hasMany: foods)
• 食物（hasMany: foodAccessoriesGroup）
• FoodAccessoriesGroup (hasMany: foodAccessory)
• 有问题：*FoodAccessory（belongsToMany | belongsTo：food_prices | food_price ------ （枢轴：[价格]，表格：food_accessory_prices，型号：Food）

测试：

**foods**
| id       | name |
| -------- | ---- |
| 1        | Pork |
| 2        | Eggs |

**accessory_groups**
| id     | name |
| -------| -----|
| 1      | Sauce|

foods_accessory_groups
| food_id  | accessory_group_id |
| -------- | --------------     |
| 1        | 1                  |
| 2        | 1                  |

**accessories**
| id       | name           | acc_group_id |
| -------- | -------------- | - |
| 1        | Mayo           | 1 |
| 2        | Ketchup        | 1 |

**foods_accessories_prices**
| food_id  | accessory_id   | price |
| -------- | -------------- | -     |
| 1        | 1              | 200   |
| 2        | 1              | 300   |
| 1        | 2              | 250   |
| 2        | 2              | 350   |

代码示例：

// get all food and relations
$foodCategories = FoodCategory::with([
  'foods',
  'foods.accessory_groups',
  'foods.accessory_groups.accessories',
  'foods.accessory_groups.accessories.food_prices' or
  'foods.accessory_groups.accessories.food_price' => function ($query) {
    // how to filter food prices by great-grandparent relation food (by food_id)
    // I know that it can't be done here, but where and how
  }
])->get();

配件动态价格取决于食物（曾祖父母关系）。 什么是这个问题的最佳实践和最优化的解决方案？ 后处理或 Laravel Eloquent 有解决方案没有太多麻烦

food (id = 1, Pork) -> 有 foods_accessory_groups(id = 1, Sauce) -> 有配件（蛋黄酱和番茄酱），蛋黄酱价格是 200 ，番茄酱的价格是300。

food (id = 2, Eggs) - ... - ma​​yo价格是250，番茄酱价格是350。

API 响应来自示例：

Answer 1

您可以使用whereHas 方法仅查询与您指定的条件有关系的FoodCategory 模型。

$foodCategories = FoodCategory::query()
    ->with([
        'foods',
        'foods.accessory_groups',
        'foods.accessory_groups.accessories',
        'foods.accessory_groups.accessories.food_prices' or
        'foods.accessory_groups.accessories.food_price' => function ($query) {
            // load only models from that relationship that match the condition(s)
            $query->where(...)
        }
    ])
    ->whereHas('foods.accessory_groups.accessories.food_price', function ($query) {
        // get only categories that have a nested relationship with condition(s)
        $query->where(...)
    })
    ->get();

Answer 2

您可以像这样直接访问accessories，并在您的 Foods 模型上显示价格

public function accessories() {
    return $this->belongsToMany( Accessory::class )->withPivot('price');
}

或在您的配件模型中执行相反的操作

public function foods() {
    return $this->belongsToMany( Food::class )->withPivot('price');
}

但由于您没有直接查询食物模型，因此您需要正确定义每个模型的关系，直到您的 FoodCategory 模型