深层关系，*孩子*关系取决于*曾祖父母* id - 与 | 加载-Laravel/雄辩

Question

I have this DB/Model structure (example):

* Food Category ------------ (id, name) - *irrelevant

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

Accessory Groups --------- (id, name, ...)

Foods_Accessory Groups - (food_id, acc_group_id) - pivot table

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

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

Models

• FoodCategory (hasMany: foods)
• Food (hasMany: foodAccessoriesGroup)
• FoodAccessoriesGroup (hasMany: foodAccessory)
• problematic : *FoodAccessory ( belongsToMany | belongsTo : food_prices | food_price ------ (pivot: [price], table: food_accessory_prices, model: Food)

Test:

**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   |

Code Example:

// 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();

Accessory dynamic price is depended on Food (great-grandparent relation). What is best practice and most optimize solution for this problem? Post-process or Laravel Eloquent has solution without too much trouble

food (id = 1, Pork) -> has foods_accessory_groups(id = 1, Sauce) -> has accessories (mayo and ketchup) where mayo price is 200 , and ketchup price is 300.

food (id = 2, Eggs) -... - mayo price is 250 , and ketchup price is 350.

API response from example:

Answer 1

You could use the whereHas method to query only FoodCategory models that have the relationship with the conditions you specify.

$foodCategories = FoodCategory::query()
    ->with([
        'foods',
        'foods.accessory_groups',
        'foods.accessory_groups.accessories',
        'foods.accessory_groups.accessories.food_prices' or
        'foods.accessory_groups.accessories.food_price' => function ($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

You can directly access the accessories with prices on your Foods model like this

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

or do the reverse inside your Accessories Model

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

but since you are not querying the food model directly you need to properly define the relationship for each model up until your FoodCategory model