SCN_TO_TIMESTAMP Function

Syntax

return_value := SCN_TO_TIMESTAMP(number);

Purpose

SCN_TO_TIMESTAMP takes an argument that represents a system change number (SCN) and returns the timestamp associated with that SCN. The returned value has the datatype TIMESTAMP.

Usage Notes

This function is part of the flashback query feature. System change numbers provide a precise way to specify the database state at a moment in time, so that you can see the data as it was at that moment.

Call this function to find out the date and time associated with an SCN that you have stored to use with flashback query.

Examples

DECLARE
   right_now TIMESTAMP; yesterday TIMESTAMP; sometime TIMESTAMP;
   scn1 INTEGER; scn2 INTEGER; scn3 INTEGER;
BEGIN
-- Get the current SCN.
   right_now := SYSTIMESTAMP;
   scn1 := TIMESTAMP_TO_SCN(right_now);
   dbms_output.put_line('Current SCN is ' || scn1);

-- Get the SCN from exactly 1 day ago.
   yesterday := right_now - 1;
   scn2 := TIMESTAMP_TO_SCN(yesterday);
   dbms_output.put_line('SCN from yesterday is ' || scn2);

-- Find an arbitrary SCN somewhere between yesterday and today.
-- (In a real program we would have stored the SCN at some significant moment.)
   scn3 := (scn1 + scn2) / 2;
-- Find out what time that SCN was in effect.
   sometime := SCN_TO_TIMESTAMP(scn3);
   dbms_output.put_line('SCN ' || scn3 || ' was in effect at ' || TO_CHAR(sometime));
END;
/

Related Topics

TIMESTAMP_TO_SCN Function