Moodle in English

thanks. In fact, I'm very new to PHP. Learning things only. what i tried is as below: (my file is at root of moodle folder)

require(__DIR__ . '/lib/dml/oci_native_moodle_database.php');

$OCI= new oci_native_moodle_database(true);

$oracle_connection= $OCI->connect('myserver', 'user', 'pass', 'oracle SID', '')) {

$students = $OCI->get_records_sql("SELECT * from students") ;

                                         echo '<pre>';

                                          print_r($students);

                                          echo '</pre>';

I'm not getting any display, or error. what corrections should I make? I have oci extension for PHP as i can see from my phpinfo()