SQL & PL/SQL

hi is there a similar  function in database as logout/login function witch is used in form

LOGOUT;

      LOGON(unserid,

            pswd||db_instance,

            FALSE);

am in oracle database 11gR2

Description



Performs the default Oracle Forms logon processing with an indicated username and password. Call this procedure from an On-Logon trigger when you want to augment default logon processing. 
Syntax



PROCEDURE LOGON
(username VARCHAR2, 
password VARCHAR2); 


PROCEDURE LOGON
(username VARCHAR2, 
password VARCHAR2, 
logon_screen_on_error BOOLEAN); 


Built-in Type unrestricted procedure 


Enter Query Mode yes 
Parameters



This Built-in takes the following arguments: 
username 
     
    Any valid username of up to 80 characters. 

password 
     
    Any valid password of up to 80 characters, including a database connect string. 

logon_screen_ on_error 
     
    An optional BOOLEAN parameter that, when set to TRUE (default), causes Oracle Forms to automatically display the logon screen if the logon specified fails (usually because of a incorrect username/password). When logon_screen_on_error is set to FALSE and the logon fails, the logon screen will not display and FORM_FAILURE is set to TRUE so the designer can handle the condition in an appropriate manner. 
Usage Notes:



When using LOGON to connect to an OPS$ database use a slash '/' for the user.name and the database name for the password.. 
LOGON Restrictions 
If you identify a remote database, a SQL*Net connection to that database must exist at runtime. Oracle Forms can have a primary connection to only one database at a time. However, multiple connections can be established for use in PL/SQL using the EXEC_SQL packages. Also, database links may be used to access multiple databases with a single connection. 
LOGON Examples 




/*


** Built-in: LOGON 
** Example: Perform Oracle Forms standard logon to the ORACLE 
** database. Decide whether to use Oracle Forms
** Built-in processing or a user exit by consulting a 
** global flag setup at startup by the form, 
** perhaps based on a parameter. This example 
** uses the 'Get_Connect_Info' procedure from the 
** GET_APPLICATION_PROPERTY example. 
** Trigger: On-Logon 
*/ 
DECLARE 
un VARCHAR2(80); 
pw VARCHAR2(80); 
cn VARCHAR2(80); 
BEGIN 
/* 
** Get the connection info 
*/ 
Get_Connect_Info(un,pw,cn); 
/* 
** If at startup we set the flag to tell our form that we 
** are not running against ORACLE, then call our 
** appropriate MY_LOGON userexit to logon. 
*/ 
IF :Global.Non_Oracle_Datasource = 'TRUE' THEN 
User_Exit('my_logon username='||un||' password='||pw); 
/* 
** Otherwise, call the LOGON Built-in 
*/ 
ELSE




/*  
** Use the following to place a slash in the username field for OPS$ logon  
*/  
IF un IS NULL THEN
un:='/';
END IF;
IF cn IS NOT NULL THEN
LOGON(un,pw||'@'||cn);
ELSE
LOGON(un,pw);
END IF;