Question

大家好，我是来拉拉维尔（Laravel）的，我正在尝试获取数据。请使用状态ID向我介绍所有具有相互关系的模型，并举例说明我有这样的表

1-状态表

1- id

2名

2-城市表

1- id

2名

3-state_cities数据透视表

1-id

2-sate_id

3-city_id

4个位置表

1-id

2名

5- city_locations数据透视表

1-id

2-city_id

3-location_id

6-密码表

1-id

2-pincode

7- location_pincodes表

1-id

2-location_id

3-pinecode_id

这是我的控制器

$states_with_cities = $states_with_cities->load(['cities.cityName','location.locationName'])->where('id',1)->get();

        $states_with_cities->transform(function($states_with_cities) {
            return [
                    'state_id' => $states_with_cities->id,
                    'state_name' => $states_with_cities->name,
                    'cities' => $states_with_cities->cities->map(function($cities,$location) {

                        return [
                            'city_id' => $cities->city_id,
                            'city_name' => $cities->cityName->name,
                            'location' => $location->locationName->map(function($locationName) use($location) {
                                return [
                                    'location_id' => $location->location_id,
                                    'location_name' => $locationName->locationName->name
                                ];
                            })
                        ];
                    }),
                ];
        });

那就是错误了

"message": "Trying to get property of non-object",
            "exception": "ErrorException",
            "file": "D:\\xampp\\htdocs\\samudaay-backend\\app\\Http\\Controllers\\API\\PincodeController.php",
            "line": 32,

Answer 1

$states_with_cities = $states_with_cities->load(['cities.cityName','location.locationName'])->where('id',1)->get();

$states_with_cities->transform(function($states_with_cities) {
    return [
        'state_id' => $states_with_cities->id,
        'state_name' => $states_with_cities->name,
        'cities' => $states_with_cities->cities->map(function($cities,$location) {
        // Location is the 'key' of the object in the collection. So it probably will be something like '0' or '1'.

            return [
                'city_id' => $cities->city_id,
                'city_name' => $cities->cityName->name,
                'location' => $location->locationName->map(function($locationName) use($location) {
                    //What you actually do here is: 0->locationName->map(...). This will result in your error
                    return [
                        'location_id' => $location->location_id,
                        'location_name' => $locationName->locationName->name
                    ];
                 })
             ];
         }),
    ];
});

第一个地图函数中的

$ location是当前正在迭代的对象的键。（请参阅：https://laravel.com/docs/5.6/collections#method-map）因此，在第32行上，您尝试调用键变量上的属性（可能为'0'或'1'之类的东西。）由于该对象不是对象，因此会导致错误。

此外，尝试映射locationName属性无法按预期工作。 locationName是属性，而不是雄辩的集合。

您可能应该这样尝试：

'location' => [
        'location_id' => $location->location_id,
        'location_name' => $location->name
    ];
})

Laravel雄辩的关系不适用于两个数据透视表

1 个答案: