The OCI8 extension for Oracle Database can be linked with Oracle's client libraries called “Oracle Instant Client”.

1. Download the Oracle 10gR2 Instant Client “basic” and “sdk” zip files from Oracle.
2. Unzip the “basic” package and rename the directory as lib/instantclient
3. Unzip the “sdk” package and rename the directory as include/instantclient
4. Build with the --with-oci8 option, e.g. --with-oci8=shared. You can also pass the Instant Client path, for example --with-oci8=F:\instantclient_10_2\sdk,shared
5. Build with the --with-oci8-11g option, e.g. --with-oci8-11g=shared. You can also pass the Instant Client path, for example --with-oci8=F:\instantclient_11\sdk,shared
6. Move the generated php_oci8.dll (or php_oci8_11g.dll) to the extensions directory and edit php.ini, setting extension_dir to that path. Enable the extension in php.ini with extension=php_oci8.dll (or php_oci8_11g.dll)

It is not possible to build statically oci8 and oci8_11g at the same time (a configure check checks it).

Instant Client is free and has a permissive license, allowing development, deployment and distribution of the Oracle libraries.

Download: Oracle Instant Client

License: “OTN Development and Distribution License Agreement for Instant Client” (Viewable as a Javascript popup prior to downloading).

The php_oci8.dll released with PHP 5.1 and 5.2 used Oracle Instant Client 10gR2 (aka 10.2). PHP 5.3 uses Instant Client 10g and 11g.