如何在 Laravel Lighthouse 中查询多透视关系

Question

嗨，我对 laravel-lighthouse 还很陌生。我已阅读文档，但不幸的是，没有有关此问题的详细信息。我的问题是如何查询多个数据透视表。我有一个属于许多其他模型的项目表。 代码如下。

class Item extends Model
    {
        public function provisions(): BelongsToMany
        {
            return $this->belongsToMany(Pwmp::class,
                'project_wise_material_provision_items', 'item_id', 'provision_id')
                ->withPivot('qty', 'unit_cost')
                ->withTimestamps()
                ->as('provision_items');
        }
        public function procurements(): BelongsToMany
        {
            return $this->belongsToMany(Pwpp::class,
                'project_wise_procurement_plan_items', 'item', 'procurement')
                ->withTimestamps()
                ->as('procurement_items')
                ->withPivot('qty', 'unit_cost');
        }
    
        public function log_sheets(): BelongsToMany
        {
            return $this->belongsToMany(Braols::class,
                'bid_receiving_and_opening_log_sheet_items', 'item', 'braols')
                ->withTimestamps()
                ->as('log_sheet_items')
                ->withPivot('qty', 'unit_cost', 'tax');
        }
        public function workshop(): BelongsToMany
        {
            return $this->belongsToMany(TransformerWorkshop::class,
                'transformer_workshop_items', 'item', 'workshop')
                ->as('workshop_items')
                ->withTimestamps()
                ->withPivot('qty', 'flow', 'type');
        }
        public function sub_office(): BelongsToMany
        {
            return $this->belongsToMany(MaterialReceiptInSubOffice::class,
                'material_receipt_in_sub_office_items', 'item', 'receipt')
                ->as('sub_office')
                ->withTimestamps()
                ->withPivot('id','qty', 'type');
        }

这是我的 GraphQL 架构

type Item{
        id: ID!
        workshop_items: [TransformerWorkShopItemsPivot]
        provision_items: [ProjectWiseMaterialProvisionItem]
        sub_office: MaterialReceiptInSubOfficeItemsPivot
    }
    
    type MaterialReceiptInSubOfficeItemsPivot{
        qty: Int
        type: Int
        id: ID
    }
    
    type ProjectWiseMaterialProvisionItem {
        qty: String
        unit_cost: String
    }
    type TransformerWorkShopItemsPivot{
        qty: Int
        type: Int
        flow: Int
    }
    

现在当我查询 api 时

```graphql material_receipt_in_sub_office_store(id: 4){ id items{ id provision_items{ unit_cost qty } sub_office{ type id qty } } } } ``` it returns the following result

{
  "data": {
    "material_receipt_in_sub_office_store": {
      "id": "4",
      "items": [
        {
          "id": "431",
          "name": "Drill Machine",
          "image": "crane2.jpg",
          "category_id": {
            "id": "993"
          },
          "provision_items": null,
          "sub_office": {
            "type": null,
            "id": null,
            "qty": null,
            "__typename": "MaterialReceiptInSubOfficeItemsPivot"
          }
        },

我无法获取多个数据透视表数据。 但是，如果我查询数据透视表，它只会返回一个数据透视表的数据。

Answer 1

首先，您似乎没有在类型定义中使用 Laravel 模型的关系。

通过指定 @belongsToMany / @hasMany 指令（在此处查看更多内容）您将能够优化您的查询。

type Item{
    id: ID!
    workshop_items: [TransformerWorkShopItemsPivot] @hasMany(relation: "workshop")
    provision_items: [ProjectWiseMaterialProvisionItem] @hasMany(relation: "provisions")
    sub_office: MaterialReceiptInSubOfficeItemsPivot @hasMany
}

我只是不确定您在关系定义中给出表别名的事实。

然后，通过执行查询，您可以根据需要获取尽可能多的主元关系。这样做从来没有遇到过关系问题。