frontend\modules\user\models\UserAccount::rules PHP Method

    public function rules()
    {
        return [[['user_id', 'created_at'], 'integer'], [['client_id', 'data'], 'required'], [['data'], 'string'], [['provider'], 'string', 'max' => 100], [['client_id'], 'string', 'max' => 255]];
    }