I installed the oracle instant client 12, but I can't connect the php with OCI8. I am using XAMPP 32bit and PHP 7.0.15. In my phpinfo() don't show the OCI section. Please, I'm stuck in this problem for a few days. :/ Thanks for all!
Well, the problem was that XAMPP as well PECL(web site) has the wrong (or outdate) DLL for OCI8. So this link here has the correctly DLLs for PHP.