How to add operation system user in atable

Question

oracle 10g and Oracle Enterprise Linux 5.4
i wouil like to add operation system user name in a oracle table so that i can monitor data in the particular table

Answer 1

Your question is unclear.
Check also v$session dynamic performance view may be you can get information from this view which you can pull into your custom table.
And your query is about finding who is connected then,
To know about the list of users that is now connected and the time when they connect to database issue the following query.
SQL> SELECT s.username, s.program, s.logon_time
FROM v$session s, v$process p, sys.v_$sess_io si
WHERE s.paddr = p.addr(+)
AND si.sid(+) = s.sid
AND s.type = 'USER';
USERNAME PROGRAM LOGON_TIM
SAMI sqlplus@testerp (TNS V1-V3) 26-NOV-10
oracle@testerp (J000) 26-NOV-10
To know only the current session user name you can issue the following query,
SQL> SELECT USERNAME from v$session where audsid = sys_context('userenv','sessionid');
USERNAME
SAMI
To know about on which schema you are connecting issue following query.
SQL> SELECT sys_context('USERENV', 'CURRENT_SCHEMA') FROM dual;
SYS_CONTEXT('USERENV','CURRENT_SCHEMA')
SAMI
To know about the connected user user for the current session issue,
SQL> SELECT sys_context('USERENV', 'SESSION_USER') FROM dual;
SYS_CONTEXT('USERENV','SESSION_USER')
SAMI
If you use SQL*plus then simply issue,
SQL> SHOW USER;
USER is "SAMI"