深層關系，*孩子*關系取決於*曾祖父母* id - 與 | 加載-Laravel/雄辯

Question

我有這個數據庫/模型結構（示例）：

*食品類別 -------------- (id, name) - *不相關

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

附件組-------- (id, name, ...)

Foods_Accessory Groups - (food_id, acc_group_id) - pivot 表

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

Foods_Accessories_Prices - (food_id, accessory_id, price ) - pivot 表

楷模

• FoodCategory（有許多：食物）
• 食物（有很多：foodAccessoriesGroup）
• FoodAccessoriesGroup（有許多：foodAccessory）
• 有問題的：*FoodAccessory ( belongsToMany | belongsTo : food_prices | food_price ------ (pivot: [price], table: food_accessory_prices, model: Food)

測試：

**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   |

代碼示例：

// 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();

配件動態價格取決於食物（曾祖父母關系）。 這個問題的最佳實踐和最優化的解決方案是什么？ 后處理或者Laravel Eloquent 都有解決辦法，不太麻煩

food (id = 1, Pork) -> has foods_accessory_groups(id = 1, Sauce) -> has accessories (mayo and ketchup) 其中蛋黃醬價格為 200 ，番茄醬價格為 300。

food (id = 2, Eggs) -... -蛋黃醬價格為 250 ，番茄醬價格為 350。

來自示例的API 響應：

Answer 1

您可以使用whereHas方法僅查詢與您指定的條件有關系的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

您可以像這樣在您的食品 model 上直接訪問帶有價格的accessories

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

或者在你的配件里面做相反的事情 Model

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

但由於您沒有直接查詢食物 model，因此您需要正確定義每個 model 的關系，直到您的FoodCategory model