I would need to connect to Oracle DB in my PHP codes. I'm using Windows Server 2012, IIS 8 with PHP Manager. I opened IIS PHP Manager, then go to PHP Extensions, then I enabled "php_oci8.dll" extension. However when I tried to connect to Oracle DB I'm getting the following PHP error: PHP Fatal error: Call to undefined function oci_connect() I just restarted the IIS using the IIS Manager, but didn't done computer reboot. Do I need to reboot? Do I also need to download "instantclient-basic-windows.x64-12.1.0.1.0.zip"? If yes, do I just need to set it to classpath "Path" where I extracted? Thank you very much in advance.