xtu_mall/app/admin/model/general/Lang.php

<?php
namespace app\admin\model\general;

use think\Model;

class Lang extends Model
{
    protected $name = 'lang';
    protected $autoWriteTimestamp = true;

    protected function setMarkAttr($value)
    {
        return strtolower(trim((string)$value));
    }

    protected function setCodeAttr($value)
    {
        return strtolower(trim((string)$value));
    }

    public static function getEnabledList()
    {
        return self::where('is_enabled', 1)->order('sort asc,id asc')->select();
    }

    public static function getDefaultMark()
    {
        $row = self::where('is_default', 1)->find();
        return $row ? $row->mark : 'cn';
    }
}