need help in automatic update

i have created a table with the system date as one of the coloumn:

create table nav_date as (SELECT TO_CHAR(SYSDATE, 'DD-MON-YYYY HH:MI:SS') "Current date" FROM dual)

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how to get the current system date in the table when ever i open that table

You can't, as the table stores the data, does not generate dynamically. You can however create a view to do that.