guangan/plugs/think-plugs-cms/src/model/CmsArticle.php

<?php

namespace plugin\cms\model;

use think\admin\Model;

class CmsArticle extends Model
{
    public function category()
    {
        return $this->belongsToMany(CmsCategory::class, CmsCateArticle::class,
            'cid', 'aid');
    }

    public function cateids()
    {
        return $this->hasMany(CmsCateArticle::class, 'aid');
    }

    public function getCateIdsAttr()
    {
        return $this->cateids->column('cid');
    }
}