Laravel属于关系不起作用

Question

I have three models that I have created Post and Comment and User. I am trying to create a relationship in between. Comment and Post they both have a field "user_id" that matches the id on the User table. Below are the relationships that I am trying to set:

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:

<?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

    <?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);
    }



}

Now as you can see a Comment belongsTo a user and a post belongsTo a user.

However when I try to create a new post via tinker (with no user created on database or logged in user) I can create a post with no problem;

That tells me that the relationship that a post must have a user and a comment must have a user as well its not working! Any idea how to fix this ?

Migrations:

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

Add the foreign key constraints in your migration to check for valid user when creating a post and to check for valid user and post when creating comments. This should solve your issue.

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');
});

Change the onDelete option based on your needs. The cascade will delete the child relationships when a parent is deleted.