Conexion PHP y Oracle DB

<?php

$conn = oci_pconnect('user', 'pass', 'localhost/XE');
if (!$conn) {
    $e = oci_error();
    trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}

$stid = oci_parse($conn, 'SELECT * FROM zapatos');
oci_execute($stid);

echo "<table class='table table-striped'>\n";
echo "<thead>";
echo "<tr>";
echo "<th>ID</th>";
echo "<th>Nombre</th>";
echo "<th>Precio</th>";
echo "<th>Stock</th>";
echo "<th>Detalles</th>";
echo "</tr>";
echo "</thead>";
while ($row = oci_fetch_array($stid, OCI_ASSOC+OCI_RETURN_NULLS)) {
    echo "<tr>\n";
    foreach ($row as $item) {
        echo "    <td>" . ($item !== null ? htmlentities($item, ENT_QUOTES) : "") . "</td>\n";
    }
    echo "</tr>\n";
}
echo "</table>\n";

?>