Laravel 5.3：独特的验证不适用于具有主键的条件！='id'

I am new to laravel and want to add validation of unique url with where clause in update case. I have tried both codes but none seems to be working.

    'page_url' => [ 'required',
                        Rule::unique('pages')->ignore($id_page,'id_page')
                ],


    'page_url' => 'required|unique:pages,page_url,null,null,id_page,!'.$id_page,

Error

Column not found: 1054 Unknown column 'pages.id' in 'where clause'

Thanks in advance.

It works by adding this in model:

 protected $primaryKey = 'id_page';