违反完整性约束：1452无法添加或更新子行：外部ke约束失败

艾哈迈德·哈塔卜

所以我有无法解决的问题，我的解决方法如下

用户可以喜欢工作或其他用户，所以我写了一个多态关系one-to-many，其中用户可以喜欢很多工作或其他用户。

这是表的定义

  public function up()
    {
        Schema::create('favorites', function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('favoritable_id');
            $table->unsignedBigInteger('user_id');
            $table->string('favoritable_type');

            $table->foreign('user_id')
                ->references('id')
                ->on('default_users')
                ->onDelete('cascade');

            $table->timestamps();
        });
    }

一个问题是，每当我尝试喜欢给定的工作时，我总是会收到此错误，

具有id的工作可以正常工作，但是第二个工作不起作用

运行正常

DefaultUser::first()->favoriteJobs()->save(Job::first())

但是这个

DefaultUser::first()->favoriteJobs()->save(Job::find(2))

给出以下错误

Illuminate/Database/QueryException with message 'SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint
fails (`dwarozh_jobs`.`favorites`, CONSTRAINT `favorites_user_id_foreign` FOREIGN KEY (`user_id`) REFERENCES `default_users` (`id`) ON DELETE CASCADE) (SQL: inser
t into `favorites` (`favoritable_id`, `favoritable_type`, `user_id`) values (1, App/Models/Job, 2))'

CanFavorite.php

<?php

namespace App\Concerns;

use App\Models\Job;

trait CanFavoriteJobs {
    public function favoriteJobs()
    {
        return $this->morphedByMany(Job::class, 'favoritable', 'favorites', 'favoritable_id', 'user_id');
    }
}

谢谢您的回答。

唐卡纳什

场景：用户可以收藏其他用户和/或工作。

favorites表格迁移


class CreateFavoritesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('favorites', function (Blueprint $table) {
            $table->primary(['user_id', 'favoritable_id', 'favoritable_type']);
            $table->foreignId('user_id')->constrained();
            $table->unsignedBigInteger('favoritable_id');
            $table->string('favoritable_type');
            $table->timestamps();
        });
    }

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

最喜欢的口才模型-获得一些关系功能


namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Favorite extends Model
{
    //use HasFactory;

    public function favoritables()
    {
        return $this->morphTo('favoritable');
    }
}

特性提供标记唱片收藏夹和收藏夹关系的功能。


namespace App;

use App\Models\User;
use Illuminate\Database\Eloquent\Relations\MorphToMany;

trait Favoritable
{
    /**
     * Get all favorites associated with the model.
     */
    public function favorites(): MorphToMany
    {
        return $this->morphToMany(User::class, 'favoritable', 'favorites')->withTimestamps();
    }

    /**
     * Mark the model record as favorite
     */
    public function favorite(?User $user = null): void
    {
        $user = $user ?: auth()->user();

        $this->favorites()->attach($user);
    }
}

使用户以及工作模型都使用该特征

use App\Favoritable;
use Illuminate\Notifications\Notifiable;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Model
{    
    use HasFactory, Notifiable, Favoritable;

    //$fillable, $hidden, $casts etc

    public function favoritesForUsers()
    {
        return $this->hasMany(Favorite::class, 'user_id', 'id')->where('favoritable_type', 'App\Models\User');
    }

    public function favoritesForJobs()
    {
        return $this->hasMany(Job::class, 'user_id', 'id')->where('favoritable_type', 'App\Models\Job');
    }
}

工作（口才）模型


namespace App\Models;

use App\Favoritable;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Job extends Model
{
    use HasFactory, Favoritable;

    //Model class definition
}

现在将已认证用户-登录用户标记为作业或用户为收藏夹

//Mark the first Job as favorited by currently logged in user
$job = Job::first();
$job->favorite();

//Mark the User with an id of 45 favorited by currently logged in user
$user = User::find(45);
$user->favorite();

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