我的关系：
内容模式=〉

class Content extends Model
{
    use HasFactory;

    protected $table = "contents";

    protected $fillable = [ "body", "camapaign_id" ];

    public function campaigns(){
        return $this->belongsTo(Campaign::class, "campaign_id");
    }
}

我的手机模型=〉

class Campaign extends Model
{
    use HasFactory;

    protected $table = "campaigns";

    protected $fillable = [ "ringba_campaign_id", "is_active" ];

    public function contents(){
        return $this->hasMany(Content::class, "content_id");
    }
}

以下是我的迁移：
内容表=〉

public function up()
    {
        Schema::create('contents', function (Blueprint $table) {
            $table->id();
            $table->timestamps();
            $table->string("body", 255);
            $table->foreignIdFor(\App\Models\Campaign::class)->nullable();
        });
    }

活动表=〉

public function up()
    {
        Schema::create('campaigns', function (Blueprint $table) {
            $table->id();
            $table->timestamps();
            $table->string("ringba_campaign_id", 255);
            $table->boolean("is_active")->default(0);
        });
    }

下面是我的内容控制器：

public function index(){
        $contents = Content::all()->sortBy("created_at");
        return view("Dashboard.Contents.contents", [
            "contents" => $contents
        ]);
    }

我正在尝试访问ringba_camapaign_id，如下所示=〉

@foreach($contents as $content) 
  {{ $content->campaign_id->ringba_campaign_id }}
 @endforeach

但我得到这个错误：试图读取int的属性