The first time we install xampp for windows, by default, the only active database connection is MySQL. Therefore, if user wants to activate connection to oracle database, user needs to set it up first. How to activate/set up oracle database connection in xampp for windows? Here are some things i did to successfully activate oracle connection:

1. To check whether your oracle setting has been activated or not, go to phpinfo, look for string oci8. If string found it indicate that connection to oracle is available, otherwise to activate connection do the following steps:
2. Open all php.ini files in xampp folder (or you can open only the currently used php.ini file by looking at the phpinfo), then make the following necessary changes:
3. Find string extension=php_oci8.dll. You’ll find there’s a semicolon ‘;‘ ahead of the string.
4. Remove the semicolon to activate the oracle extension.
5. Save the php.ini file.
6. Install oracle client. Simply just install it on your computer, there is no settings required. You can download it from this oracle site.
7. Activate or restart xampp.
8. To make sure that connection to oracle database has successfully activated, go to phpinfo. Find string: oci8. If founded, then now xampp can communicate with oracle database.

Works for me