index.php

<?php
namespace connections;
require_once 'ConexaoDB.php';

$conn = new ConexaoDB();

try{
//$result = $conn->getConn()->exec("insert into produto");
$result = $conn->getConn()->query("SELECT * FROM produto");

if($result){
    foreach ($result as $row){
       echo $row['descricao'] . $row['codigo_barras'];
        }
    }
}

catch (PDOException $e){
    print"erro: " . $e->getMessage() . "<br />";
}

$conn = null;