ONE ALTERNATIVE OF CONNECT IN ORACLE RAC "Real Application Clusters"
<?php
$dbstr ="(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST =ip1)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = banco)
(INSTANCE_NAME = banco1)))";
$dbstr1 ="(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST =ip2)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = banco)
(INSTANCE_NAME = banco2)))";
if(!@($conn = oci_connect('user','password',$dbstr1)))
{ $conn = oci_connect('user','password',$dbstr) or die (ocierror()); }
?>