test_app/app/Models/DownGrade.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class DownGrade extends Model
{
    //定义表
    protected $table = "down_grade";
    //定义主键
    protected $primaryKey = "id";
    protected $fillable = ['user_id','admin_id','admin_name','type','money','season','down_money'];
}