test/app/Http/Models/SiteEnterprise.php

<?php

namespace App\Http\Models;

use Illuminate\Database\Eloquent\Model;

class SiteEnterprise extends Model
{
    protected $table = 'sites_enterprise';
    protected $primaryKey = 'site_id';
    public $incrementing = false;
    protected $guarded = [];

    public function business()
    {
        return $this->belongsTo(Business::class,'business_id','id');
    }

}