This is a very lightweight solution to connect to an Oracle Database using OCI8.
composer require rubyan/simple-oracle:dev-master
$config['host'] = 'localhost';
$config['username'] = 'demo';
$config['password'] = 'demo';
$config['port'] = 1521;
$config['instance_name'] = 'xe';
$config['charset'] = 'UTF8';
$db = new \Rubyan\Oracle\Oracle($config);
$sql = 'SELECT * FROM HR.JOBS';
$db->execute($sql);