Re[2]: Handling Daylight Savings Time -Reply

Tim --

The fundamental question on this is: can Oracle internally determine the number of seconds encountered since the last midnight, or are all time calculations based on the OS clock? It is my suspicion that it is the latter, and therefore, timestamp is largely unique but will have multiplicity by definition. This makes it non-unique (as in "there will never be two presidents with the same last name except Adams and Roosevelt"). So, IF THIS IS THE CASE, the question then becomes, how do you make something (timestamp in this case) unique which isn't unique by nature? That's fairly easy...

1. don't make it unique
2. use a composite key which will be unique (president_name/date_elected or timestamp/timezone);
3. create another field which has nothing to do with the non-unique field and let it be your primary key (sequence);

or

4) go to absolute time, which *is* unique by nature (set your OS clock

    to GMT and don't change to daylight savings) then write the appropriate     algorithm for conversion.

Now, having said that, I need to go back to my first question and ask any OraHak WHO HAS ACTUALLY SEEN THE INTERNALS... does Oracle count ticks in one of the daemon processes, or is it based on the system clock? If it counts ticks, you can just use SSSSS.

Good luck...
Bambi. Received on Wed Jan 31 1996 - 19:09:51 CST