DevOps, CI/CD and Automation

Hello expert,i have a problem when install oci8.so on ubuntu 12,i'm trying with tutuariol
https://help.ubuntu.com/community/PHPOracle

but when i finished,i was creating a file with content
*<?php*
*$db = '(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp) (HOST=192.168.1.17)*
*(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=apporcl)*
*(SERVER=DEDICATED)))';*
*$username = 'system';*
*$password = '123456';*
oci_connect($username, $password, $db );

echo 'a';
*?>*
but i don't know why ? althought true or false syntax,it still not show error message,in general,it can't echo result alter i call oci_connect function

OS : Oracle Linux
DB : 11g
Thank