app-api/app/Models/Course/Collection.php

<?php

namespace App\Models\Course;

use Carbon\Carbon;
use Illuminate\Database\Eloquent\Model;
use DateTimeInterface;

class Collection extends Model
{
    protected $connection = 'mysql_c';
    protected $table='collection';
    protected $guarded=[];
    protected $appends = ['create_at_humans'];

    protected function serializeDate(DateTimeInterface $date): string
    {
        return $date->format('Y-m-d H:i:s');
    }
    public function getCreateAtHumansAttribute($key)//此处的Pic与追加字段'pic' 相对应
    {
        return Carbon::createFromFormat('Y-m-d H:i:s', $this->attributes['created_at'])->diffForHumans();
    }
//    public function getCreatedAtAttribute($value){
//        return Carbon::createFromFormat('Y-m-d H:i:s', $value)->diffForHumans();
//    }

    public function user(){
        return $this->hasOne(App\Models\User::class,'id','user_id')->withTrashed();
    }

    public function course(): \Illuminate\Database\Eloquent\Relations\HasOne
    {
        return $this->hasOne(Course::class,'id','course_id','deleted_at')->withTrashed();
    }
}