Laravel屬於關系不起作用

Question

我有三個模型，我創建了帖子和評論和用戶。 我想在兩者之間建立一種關系。 注釋和發布它們都有一個字段“user_id”，它匹配User表上的id。 以下是我要設置的關系：

Comment.php：

<?php

namespace App;


class Comment extends Model
{
    //
    public function post(){

        return $this->belongsTo(Post::class);
    }



    public function user(){ 

        return $this->belongsTo(User::class);
    }
}

post.php中：

<?php

namespace App;

class Post extends Model
{

    public function comments(){

        return $this->hasMany(Comment::class);
    }

    public function addComment($body, $name, $email){




        $this->comments()->create(compact('body','name','email'));
    }

       public function user(){ // $comment->user->name

        return $this->belongsTo(User::class);
    }
}

user.php的

    <?php

namespace App;
use App\Post;

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

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name', 'email', 'password',
    ];

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

    public function post(){

        return $this->hasMany(Post::class);
    }



}

現在你可以看到一個評論屬於一個用戶和一個帖子屬於一個用戶。

但是，當我嘗試通過修補程序創建一個新帖子時（沒有在數據庫上創建用戶或登錄用戶）我可以創建一個沒有問題的帖子;

這告訴我，帖子必須有用戶和評論的關系必須有一個用戶以及它不工作！ 知道如何解決這個問題嗎？

遷移：

create_posts_migration：

<?php

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

class CreatePostsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('posts', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('user_id');
            $table->string('title');
            $table->text('body');
            $table->string('image');
            $table->timestamps();
        });
    }

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

create_comment_migration：

<?php

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

class CreateCommentsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('comments', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('post_id');
            $table->integer('user_id');
            $table->string('email');
            $table->string('name');
            $table->string('body');
            $table->timestamps();
        });
    }

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

Answer 1

在遷移中添加外鍵約束以在創建帖子時檢查有效用戶，並在創建注釋時檢查有效用戶和發布。 這應該可以解決您的問題。

Schema::create('posts', function (Blueprint $table) {
    $table->increments('id');
    $table->unsignedInteger('user_id');
    $table->string('title');
    $table->text('body');
    $table->string('image');
    $table->timestamps();

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

Schema::create('comments', function (Blueprint $table) {
    $table->increments('id');
    $table->unsignedInteger('post_id');
    $table->unsignedInteger('user_id');
    $table->string('email');
    $table->string('name');
    $table->string('body');
    $table->timestamps();

    $table->foreign('post_id')->references('id')->on('posts')->onDelete('cascade');
    $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
});

根據您的需要更改onDelete選項。 刪除父cascade時， cascade將刪除子關系。