Description
resource 
oci_pconnect ( string username, string password [, string db [, string charset [, int session_mode]]] )
     oci_pconnect() creates a persistent connection 
     to an Oracle server and logs on. Persistent connections are cached 
     and re-used between requests, resulting in reduced overhead on each 
     page load; a typical PHP application will have a single persistent 
     connection open against an  Oracle server per Apache child process 
     (or PHP FastCGI/CGI process). See the Persistent Database 
     Connections section for more information.
    
     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.
    
     Parameter session_mode is available since version
     1.1 and accepts the following values: OCI_DEFAULT,
     OCI_SYSOPER and OCI_SYSDBA.
     If either OCI_SYSOPER or
     OCI_SYSDBA were specified,
     oci_connect() will try to establish privileged
     connection using external credentials. Privileged connections are
     disabled by default. To enable them you need to set oci8.privileged_connect 
     to On.
    
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: 
      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.
     
     See also oci_connect() and
     oci_new_connect().