neiyou_user_web/app/Models/Country.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

/**
 * 国家/地区.
 */
class Country extends Model
{
    public $timestamps = false;
    public $incrementing = false;
    protected $table = 'country';
    protected $primaryKey = 'code';
    protected $keyType = 'string';
    protected $guarded = [];

    public function nodes()
    {
        return $this->hasMany(Node::class, 'country_code');
    }
}