无法从 eloquent 个关系中获取数据

Question

我尝试使用 eloquent 关系

获取向 auth 发送消息的特定用户

这是消息模态

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Message extends Model
{
    
    protected $guarded = [];
    public function fromContact()
    {
        return $this->hasOne(User::class, 'id', 'from');
    }
}

这是消息迁移

<?php

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

class CreateMessagesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('messages', function (Blueprint $table) {
            $table->bigIncrements('id');
        $table->integer('from')->unsigned();
            $table->integer('to')->unsigned();
            $table->text('text');
            $table->text('img')->nullable();
            $table->timestamps();
        });
    }

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

并且我不更改用户模式我尝试使用 where() 函数但没有用

Answer 1

我认为你在滥用 eloquent 关系。

One To Many

A one-to-many relationship is used to define relationships where a single model is the parent to one or more child models.

试试这个。

// User model.
class User extends Authenticatable
{
// ...
    public function sentMessages()
    {
        return $this->hasMany(Message::class, 'from', 'id');
    }
    public function receivedMessages()
    {
        return $this->hasMany(Message::class, 'to', 'id');
    }
}

// Message model.
class Message extends Model
{
    use HasFactory;
    public function fromContact()
    {
        return $this->belongsTo(User::class, 'from', 'id');
    }

    public function toContact()
    {
        return $this->belongsTo(User::class, 'to', 'id');
    }
}

// Message create table migration.
class CreateMessagesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('messages', function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('from');
            $table->unsignedBigInteger('to');
            $table->text('text');
            $table->text('img')->nullable();
            $table->timestamps();

            $table->foreign("from")
                ->references("id")
                ->on("users")
                ->onDelete("cascade");

            $table->foreign("to")
                ->references("id")
                ->on("users")
                ->onDelete("cascade");
        });
    }

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

// Sample query
App\Models\Message::find(1)->with("fromContact", "toContact")->first();

// Sample output.
/*
=> App\Models\Message {#4322
     id: 1,
     from: 2,
     to: 3,
     text: "foo",
     img: null,
     created_at: null,
     updated_at: null,
     fromContact: App\Models\User {#4338
       id: 2,
       name: "stevenmwesigwa",
       email: "jwaters@gmail.com",
       email_verified_at: null,
       created_at: "2021-05-14 15:27:35",
       updated_at: "2021-05-14 15:27:35",
     },
     toContact: App\Models\User {#4339
       id: 3,
       name: "john ripper",
       email: "steven.mwesigwa@f.com",
       email_verified_at: null,
       created_at: "2021-05-14 15:30:18",
       updated_at: "2021-05-14 15:30:18",
     },
   }
*/

// Sample query 2.
App\Models\User::with(
    [
        "sentMessages" => function($query){
        $query->with("fromContact", "toContact");
    }])
    ->where("id", 2)
    ->first();

// Sample output 2.
/*
=> App\Models\User {#4357
     id: 2,
     name: "stevenmwesigwa",
     email: "jwaters@gmail.com",
     email_verified_at: null,
     created_at: "2021-05-14 15:27:35",
     updated_at: "2021-05-14 15:27:35",
     sentMessages: Illuminate\Database\Eloquent\Collection {#4369
       all: [
         App\Models\Message {#4363
           id: 1,
           from: 2,
           to: 3,
           text: "foo",
           img: null,
           created_at: null,
           updated_at: null,
           fromContact: App\Models\User {#4343
             id: 2,
             name: "stevenmwesigwa",
             email: "jwaters@gmail.com",
             email_verified_at: null,
             created_at: "2021-05-14 15:27:35",
             updated_at: "2021-05-14 15:27:35",
           },
           toContact: App\Models\User {#4380
             id: 3,
             name: "john ripper",
             email: "steven.mwesigwa@f.com",
             email_verified_at: null,
             created_at: "2021-05-14 15:30:18",
             updated_at: "2021-05-14 15:30:18",
           },
         },
         App\Models\Message {#4372
           id: 2,
           from: 2,
           to: 4,
           text: "bar",
           img: null,
           created_at: null,
           updated_at: null,
           fromContact: App\Models\User {#4343
             id: 2,
             name: "stevenmwesigwa",
             email: "jwaters@gmail.com",
             email_verified_at: null,
             created_at: "2021-05-14 15:27:35",
             updated_at: "2021-05-14 15:27:35",
           },
           toContact: App\Models\User {#4382
             id: 4,
             name: "denis parter",
             email: "ajoluvya@gmail.com",
             email_verified_at: null,
             created_at: "2021-05-14 16:16:29",
             updated_at: "2021-05-14 16:16:29",
           },
         },
       ],
     },
   }
*/

无法从 eloquent 个关系中获取数据

can't fetch data from eloquent relationships

laravel

eloquent-relationship