Server Administration :: Insert User ID Automatically In Table?

I have a table with table_ID, date_created, user_id.

I have sequence, and a BEFORE INSERT trigger, which uses the seq to increment the table_ID by 1, everytime the webpage is saved.

ques:
(1).If i have date_creted defaulted to sysdate in the table, do I need to have it in the trigger?
-- Update create_date field to current system date
:NEW.DATE_CREATED := sysdate;

(2).How can I insert the user_id in the table, each time user SAVE the page ? web page procedure is getting the user info at the beginning. can i add it in the trigger

DECLARE
v_username varchar2(10);
BEGIN

[Code]....