该集合实例上不存在属性[firstName]

问题描述

我的用户模型：

<?php

namespace App\Models;

use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'firstName','secondName','email','city','phoneNumber','password','profilePicture'
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password','remember_token',];

    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [
        'email_verified_at' => 'datetime',];


    public function ratings()
    {
        return $this->belongsToMany(Ratings::class,'ratings_has_users','users_id','ratings_id')->withTimestamps();
    }

}

我的评分模型：

<?php

namespace App\Models;
use Illuminate\Database\Eloquent\Model;

class Ratings extends Model
{
    public function user(){
        return $this->belongsToMany(User::class,'ratings_id')->withTimestamps();
    }
}

迁移以创建表“ ratings_has_users”

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateRatingsHasUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('ratings_has_users',function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('users_id');
            $table->unsignedBigInteger('ratings_id');
            $table->timestamps();
        });

        Schema::table('ratings_has_users',function (Blueprint $table) {
            $table->foreign('users_id')
                ->references('id')
                ->on('users');
        });

        Schema::table('ratings_has_users',function (Blueprint $table) {
            $table->foreign('ratings_id')
                ->references('id')
                ->on('ratings');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('ratings_has_users');
    }
}

迁移到创建“用户”表

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('users',function (Blueprint $table) {
            $table->id();
            $table->string('firstName',55);
            $table->string('secondName',55);
            $table->string('email',55)->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('city',55);
            $table->text('description')->nullable();
            $table->string('phoneNumber',11);
            $table->string('profilePicture',255)->default('profile.jpg');
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('users');
    }
}

迁移以创建“评分”表：

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateRatingsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('ratings',function (Blueprint $table) {
            $table->id();
            $table->integer('stars');
            $table->mediumText('note');
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('ratings');
    }
}

然后在刀片中进行编码：

@foreach($ratings as $rating)
    {{ dd($rating->user->firstName) }}
@endforeach

我不知道为什么会看到此错误消息：此集合实例上不存在属性[firstName]。 （查看：/data/www/twoj-trener/resources/views/trainer_page/reviews.blade.php）

当我更改此代码时：

@foreach($ratings as $rating)
    {{ dd($rating->user) }}
@endforeach

我知道了：

Illuminate\Database\Eloquent\Collection {#1291 ▼
  #items: []
}

解决方法

评级具有用户（更好的名称为用户，因为属于ToMany ）。如果 belongsToMany 关系，则该关系方法（在这种情况下为 user ）将提供集合（列出相关记录）。

您可以执行以下操作

from pyspark.sql.functions import col

rows = [
    ("Ali",[100]),("Barbara",1,[300,250,100]),("Cesar",[350,("Dongmei",[400,("Eli",2,[250]),("Florita",[500,300,("Gatimu",3,100])
    ]
df = spark.createDataFrame(rows,["name","department","score"])

df.orderBy(col("department"),col("name").desc()).show()

,

评分与用户之间的关系应为users()（以S表示复数），因为它是一个带有数据透视表的beforeToMany。

如果您希望每个用户的分级都是唯一的，请考虑更改分级表的迁移

    public function up()
    {
        Schema::create('ratings',function (Blueprint $table) {
            $table->id();
            $table->integer('stars');
            $table->mediumText('note');
            $table->unsignedBigInteger('user_id');
            $table->timestamps();

            $table->foreign('user_id')->references('id')->on('users');
        });
    }

并将关系更改为belongsTo

如果您的结构正确无误，则需要先获取用户，然后才能访问其属性

@foreach($ratings as $rating)
    {{ dd($rating->users->first() ?? $rating->users->first()->firstName) }}
@endforeach