WHO COLUMNS

WHO columns are used to track the information updated or inserted by the users against the tables. FND_STANDARD package is used for this purpose. FND_STANDARD.SET_WHO Procedure is used to update the WHO columns in a Table when a DML operation s (i.e. INSERT, UPDATE) performed.

        1) Created by

        2) Creation date

        3) Last _updated_by

        4) last_update_date

        5) last_update_login

Use fnd_profile.VALUE (‘USER_ID’) for retrieving the user_id which will be used by created_by column.
Creation date and last_update_date will be normally SYSDATE.
last_updated_by is same as created_by.
Use USERENV (‘SESSIONID’) for getting the last_update_login id.