baoshi-was/app/UserDutyCheck.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class UserDutyCheck extends Model
{
    protected $fillable=[
        'user_id','checked_at','confirmed_by','type','source'
    ];
    protected $appends=[
        'user_name'
    ];

    public function user(){
        return $this->belongsTo('App\User','user_id','id');
    }

    public function getAttribute()
    {
        return $this['user']?$this['user']['name']:null;
    }
}