oracle trigger
CREATE OR REPLACE TRIGGER my_schema.trigger_name AFTER LOGON ON DATABASE
BEGIN
INSERT INTO my_log_table
VALUES (USER AS CONNECTED_USER,
sys_context('USERENV', 'SESSIONID') AS SESSION_ID,
substr(sys_context('USERENV', 'OS_USER'), 1, 50) AS OS_USER,
substr(sys_context('USERENV', 'HOST'), 1, 30) AS HOST,
SYSDATE AS LOGON_DATE);
END;
ALTER TRIGGER my_schema.trigger_name ENABLE;