<?php
// Creación de la tabla con:
//   CREATE TABLE mytab (c1 NUMBER, c2 FLOAT, c3 NUMBER(4), c4 NUMBER(5,3));
$conn = oci_connect("hr", "hrpwd", "localhost/XE");
if (!$conn) {
    $m = oci_error();
    trigger_error(htmlentities($m['message']), E_USER_ERROR);
}
$stid = oci_parse($conn, "SELECT * FROM mytab");
oci_execute($stid, OCI_DESCRIBE_ONLY); // Uso de OCI_DESCRIBE_ONLY si ninguna fila es recuperada
$ncols = oci_num_fields($stid);
for ($i = 1; $i <= $ncols; $i++) {
    echo oci_field_name($stid, $i) . " "
        . oci_field_precision($stid, $i) . " "
        . oci_field_scale($stid, $i) . "<br>\n";
}
// Muestra:
//   C1    0 -127
//   C2  126 -127
//   C3    4    0
//   C4    5    3
oci_free_statement($stid);
oci_close($conn);
?>