oci_pconnect() creates a new persistent connection to an Oracle server and logs on. The optional third parameter can either contain the name of the local Oracle instance or the name of the entry in tnsnames.ora. If the third parameter is not specified, PHP uses environment variables ORACLE_SID and TWO_TASK to determine the name of local Oracle instance and location of tnsnames.ora accordingly.
Using Oracle server version 9.2 and greater, you can indicate charset parameter, which will be used in the new connection. If you're using Oracle server < 9.2, this parameter will be ignored and NLS_LANG environment variable will be used instead.
oci_pconnect() returns connection identifier or FALSE on error.
Note: Note, that these kind of links only work if you are using a module version of PHP. See the Persistent Database Connections section for more information.
Note: In PHP versions before 5.0.0 you must use ociplogon() instead. This name still can be used, it was left as alias of oci_pconnect() for downwards compatability. This, however, is deprecated and not recommended.