如果关系是对多的，为什么用belongsTo我得到一个数组

Question

如果关系是一对多，为什么belongsTo返回数组？

IlluminateDatabaseEloquentCollection {#1288
#items: array:1 [
0 => AppModelsBrand {#1289
#connection: "mysql"
#table: "brands"
#primaryKey: "id"
#keyType: "int"
+incrementing: true
#with: []
#withCount: []
+preventsLazyLoading: false
#perPage: 15
+exists: true
+wasRecentlyCreated: false
#escapeWhenCastingToString: false
#attributes: array:4 [
"id" => 16
"title" => "tenetur"
"created_at" => "2022-03-09 18:54:32"
"updated_at" => "2022-03-09 18:54:32"
]
#original: array:4 [
"id" => 16
"title" => "tenetur"
"created_at" => "2022-03-09 18:54:32"
"updated_at" => "2022-03-09 18:54:32"
]
....

我知道hasMany((关系会返回一个模型，所以为了尝试和错误，我在我的Item模型上为hasOne更改了belongsTo，似乎希望Brands表有一个Item_id，但这没有意义。

一件物品只有一个品牌。一个品牌会有很多商品。

项目

+----------+----------------------------------------+-------+
| brand_id | sku                                    | price |
+----------+----------------------------------------+-------+
|       1  | Wuckert, Russel and Murray             |  6.52 |
|       2  | McGlynn Group                          | 34.69 |
|       2  | Walker-Murphy                          | 86.57 |
|       4  | Langworth PLC                          |  1.61 |
+----------+----------------------------------------+-------+

品牌

+----+--------------+---------------------+---------------------+
| id | title        | created_at          | updated_at          |
+----+--------------+---------------------+---------------------+
|  1 | impedit      | 2022-03-09 18:54:32 | 2022-03-09 18:54:32 |
|  2 | sit          | 2022-03-09 18:54:32 | 2022-03-09 18:54:32 |
|  3 | tenetur      | 2022-03-09 18:54:32 | 2022-03-09 18:54:32 |
|  4 | odio         | 2022-03-09 18:54:32 | 2022-03-09 18:54:32 |
+----+--------------+---------------------+---------------------+

我的模型是这样定义的。

<?php
namespace AppModels;
use IlluminateDatabaseEloquentFactoriesHasFactory;
use IlluminateDatabaseEloquentModel;
class Brand extends Model
{
use HasFactory;
/**
* Get the items associated with the brand.
*/
public function items()
{
return $this->hasMany(Item::class);
}
}

<?php
namespace AppModels;
use IlluminateDatabaseEloquentFactoriesHasFactory;
use IlluminateDatabaseEloquentModel;
class Item extends Model
{
use HasFactory;
/**
* Get the brand associated with the item.
*/
public function brand()
{
return $this->belongsTo(Brand::class);
}
}

Answer 1

错误来自于使用方括号的方式。尝试作为

$newitem->brand;

Doku：一旦定义了关系，我们就可以使用Eloquent的动态属性来检索相关记录。动态属性允许您访问关系方法，就好像它们是在模型上定义的属性一样：